Cloudy water in an aquarium: what to do?

  1. The water in the aquarium becomes cloudy: reasons
  2. Turbidity in the aquarium and its types
    1. Green water in the aquarium
    2. The water in the aquarium is cloudy, white
    3. The water turns yellow
    4. Bubbles on the surface of the water
    5. Film on water
  3. What to do if the water in the aquarium becomes cloudy?

Diseases, death of fish, plants, microorganisms invisible to the eye - such negative consequences can be caused by cloudy water in the aquarium (what to do in this case you will read in the article). Experienced aquarists assure: it is necessary to act thoughtfully, promptly, listening to the advice of professionals.

Do not panic if the water in the aquarium becomes cloudy. All fish breeders can face a similar problem. On the contrary, you need to find out as quickly as possible why the water in the aquarium becomes cloudy, do everything necessary to restore the water balance, and clean the tank.

The water in the aquarium becomes cloudy: reasons

Why is the aquarium cloudy? Often, inexperienced breeders who are faced with a similar phenomenon for the first time are interested in this. The reasons for this are many, ranging from swimming in a glass tank of small particles of algae, ending with the reproduction of unpleasant harmful bacteria.

muddy water - photo

Cloudy water in an aquarium - photo

one Why does the water in an aquarium turn cloudy quickly? It is possible that the reason lies in the presence in the tank:

A common cause of turbidity is poor soil washing. Take the time and effort to clean up. Inaccurate pouring into a glass fish house from a clean container can worsen the quality of water. Pour the liquid with the utmost care, trying not to spray, avoid falling on the edge of the glass tank. Such turbidity is not capable of leading to unpleasant consequences for aquarium fish. After a few days, the dregs will settle, fall into the filter, and evaporate.

2 Cloudy water in an aquarium after start-up is common. It occurs as a result of pouring fresh water into the reservoir. If this happens, do not rush to the store for the funds recommended on numerous thematic resources. Wait a few days. In a couple of days, the frightening sediment will sink to the bottom, and soon it will completely evaporate. Do not be alarmed if the water in the aquarium becomes cloudy on the second day, everything will certainly return to normal.

Many novice breeders, seeing the dregs, make a gross mistake - they begin to change the water. The result of such actions may be exactly the opposite: the number of bacteria in the aquarium will increase, the cloudiness will increase. Experienced ichthyologists recommend forgetting about independence, trusting qualified specialists.

3 "The water in the aquarium becomes cloudy, what should I do?" - this question is often asked by breeders who have bought gold, veil-tails, cichlids - rather mobile fish, vigorously moving in their own glass house. They regularly burrow into the ground, mix it, causing turbidity in this way. The only reasonable way out in such a situation is a filter. Purchase it, install it, do not forget to turn it on in time. Without the help of modern filtering devices, it will be difficult to clean the aquarium from cloudiness caused by the movements of the veil tails.

muddy water - photo

Cloudy water in an aquarium - photo

Overpopulation of the aquarium can become the reason for the spread of turbidity. Having bought it, do not rush to acquire countless fish, algae. If the aquarium is small, and there are plenty of inhabitants in it, then there is a high probability that the filter will not be able to properly purify the water. As a result, it can acquire a greenish tint and become cloudy. To prevent this from happening, do not buy dozens of underwater inhabitants, take care of the aquarium, clean it in a timely manner.

4The question "Why is the water in the aquarium cloudy?" ask any breeders. This process can be caused by:

  • Abundant feeding of underwater inhabitants;
  • Poor cleaning of the glass tank after the fish feeding procedure.

The golden rule of ichthyologists: it is better to underfeed the inhabitants of the underwater world than to overfeed. If this happens, do not rush to panic. Arrange a fasting day for the fish. They will not receive much harm, but the bacteria will die out, the biological balance of the water will be restored.

5Is the aquarium water cloudy? Take a closer look at the decorations purchased for the glass tank. The cause of the appearance of turbidity can be a poor-quality, not carefully processed decoration. It is more correct to throw the plastic snag into the trash can. Try not to purchase low-quality products, they can significantly complicate the life of underwater inhabitants, the breeders themselves. The wooden decoration can be left by boiling in boiling water.

muddy water - photo

Cloudy water in an aquarium - photo

6An unpleasant sediment often forms in an old aquarium, especially if the glass tank has not been looked after for a long time, or if the breeder has resorted to treating the fish using certain chemicals. Many of these drugs have unpleasant side effects, disrupt the biological balance, and form an unfavorable microflora. The result is turbidity that can scare aquarists.

Turbidity in the aquarium and its types

one Green water in the aquarium. Can seriously scare novice breeders. Many inexperienced connoisseurs of the underwater world, having discovered that the fish swim in an unpleasant greenish turbidity, are ready to do anything to purify the water. It's actually not that scary. Why does the water in the aquarium turn green, what to do, how to save the glass tank and its inhabitants? The main reason for the acquisition of a greenish color by water is the rapid reproduction of ordinary green algae. It occurs as a result:

  • Excessive lighting, regular sun rays on the water;
  • The process of rotting food, dead leaves of underwater plants.

It is not difficult to figure out why the water in the aquarium turns green. What to do? There are several ways to clear the tank from the mud. Usually ichthyologists resort to the natural - they launch planktonic crustaceans, daphnia, to the fish.

Green water in the aquarium muddy water - photo

Green water - photo

2 Aquarium water muddy ,white - what can this talk about? The phenomenon usually occurs the day after the first start-up of the aquarium. Fish and plants are trying to adapt to new, unfamiliar conditions. As a result, a favorable breeding ground is created for the active reproduction of bacteria. However, their appearance is not a reason to be upset. Whitish water in an aquarium is normal. The dregs usually go away on their own, after one to two weeks. If water acquires this shade, ichthyologists forbid touching the reservoir, carrying out the procedure for replacing the water. Otherwise, the process of improving the water balance will be delayed indefinitely. If your aquarium water turns white, try to be patient, wait. If after the due date the shade of the water does not change, you will need to resort to the help of professionals.

muddy water - photo muddy water - photo

Cloudy, white water - photo

3 Turns yellow water in the aquarium. This can happen as a result of:

  • Selection of low-quality feed;
  • Bad filtration, its complete absence;
  • Installations at the bottom of cheap decorations, driftwood;
  • Insufficient quality care.

What to do if the water in the aquarium turns yellow? Try not to skimp on food, decorations, buy high-quality goods recommended by professionals, for example, our specialists. When feeding underwater inhabitants, turn off the internal filter, then it will not get clogged with food. You can arrange a fasting day for the fish, replace a third of the water volume. Please note: it must be fresh, settled, have a similar temperature. If the water in an aquarium that has settled down turns yellow, keep in mind: timely maintenance of glass tanks can help, which will not be easy to perform on your own. Unprofessional actions can damage the aquarium.

muddy water - photo muddy water - photo

Yellow water in aquarium - photo

4 Bubbles on the surface water in the aquarium. This problem is faced by inexperienced and professional breeders. There are many reasons why water bubbles in an aquarium, ranging from the lifespan of a glass tank to poor maintenance of the underwater world. It happens that the water begins to foam in the aquarium, which was launched a few days ago. This is a sign that some substances have not disappeared from the water, for example, ammonia, nitrates, nitrites. Then the only way to get rid of bubbles on the surface of the water is to be patient, after a few days they should disappear. For an old aquarium, it all depends on the exact cause of the bubbles. Try to purchase high-quality food, decorations (including wooden, plastic driftwood), regularly clean the glass tank, monitor the operation of filters.

muddy water - photo

Bubbles on the surface in the aquarium - photo

5 Film on the water in the aquarium occurs due to:

  • Poor mixing of water;
  • The use of fatty feed;
  • Clusters of tiny, invisible algae.

A film on the surface of the water in the aquarium can also appear as a result of the use of low-quality decorations and equipment. Dealing with her is not easy. Try to pick up quality food, better granular, filter the water thoroughly. You can buy ampullary snails, effectively fighting the surface film in a glass tank. If the above steps do not help, you will have to seek the help of professional ichthyologists who are able to understand the exact cause of the formation of an unpleasant film, and propose competent measures aimed at eliminating it.

What to do if the water in the aquarium becomes cloudy?

How to make the water in an aquarium clear?

It all depends on:

  • The reasons for the appearance of turbidity;
  • Her shade;
  • The degree of opacity of the glass reservoir.

Many ichthyologists assure: if you are thinking about how to make the water in an aquarium crystal clear, then you should know that the right way to restore water balance in most cases is to change the water. What is this process, how to correctly carry it out, is it within the power of novice breeders? Let's find out.

So, suppose that as a result of turbidity, you need to partially replace the water in the glass tank. How often should the aquarium water be changed? There are two types of water replacement - partial, full. The latter is carried out if the inhabitants of the underwater world (especially if they are expensive fish) are seriously ill. It is necessary to correctly partially renew the water a couple of times a week, and not more than by 20-30%. More frequent changes can result in poor water quality.

What kind of water should I put in my aquarium?

One thing can be said with certainty: it should be crystal clear, free from chlorine, other harmful substances, with an excess present in the liquid flowing out of ordinary taps.

First of all, the water that you want to pour into the aquarium must be defended so that chlorine will disappear from the liquid.

Changing the water in the aquarium - photo

How to defend aquarium water?

This may take several days, since in the liquid entering the water supply, in addition to chlorine, there are plenty of other substances dangerous for underwater inhabitants: ammonia, nitrates. After five to seven days, you can pour settled water into the tank.

While the water is settling, you should:

  • Clean filters from dirt, feed residues, plaque;
  • Gently wipe down the inner walls of the aquarium;
  • Tidy up living plants: cut, remove microscopic particles of dead algae;
  • Work with the ground.

When you understand how to defend the water for the aquarium, put in order the contents of the glass tank, you can begin the process of renewing the water. Please note that the temperature of the settled water should not differ from the temperature in the aquarium. Only a slight deviation is possible - by one or two degrees.

As you can see, changing the water in an aquarium is not an easy process. It is difficult for a breeder, especially an inexperienced one, to independently observe all the rules for cleaning, replacing water in the tank. The hardest thing is for aquarists who have purchased expensive, very whimsical fish, rare plants. Novice breeders can spend a lot of time on cleaning the tank from mud, and incur significant losses. Therefore, the right decision may be to contact a specialist. Qualified ichthyologists will be able to replace the water in the tank as quickly as possible, painlessly for aquarium fish and other underwater inhabitants, cleanse it of turbidity, and put it in order.

Cloudy water in an aquarium - video

As you have already seen, the reasons for the cloudy water in the aquarium can be completely different. It all depends on the food, the degree of purity of the soil, the quality of the snags, and other decorations. One of the most common ways to cope with turbidity is to replace a small volume of water, a difficult procedure that requires considerable knowledge of ichthyology from the aquarist, well-planned actions, and the presence of certain equipment. It is more reasonable to entrust the "resuscitation" of the glass tank to professionals who are capable of efficiently, with a guarantee, put the aquarium in order, establish water balance, and give the underwater inhabitants a long and comfortable life.


Why does the water become cloudy in the aquarium and what to do about it?

Why does the water become cloudy in the aquarium and what to do about it?

Clouding of the aquarium water is very common and can lead to illness and even death of the entire aquarium community. Therefore, it is important to learn how to quickly recognize the cause of contamination, and take action as quickly as possible to eliminate the problem.

Clouding reasons

Most often, the problem of cloudy water is faced by inexperienced aquarium owners who have recently bought a new aquarium and launched it. but sometimes water becomes cloudy in established ecosystems that exist in established and mature reservoirs ... The reasons for such an unpleasant phenomenon can be both mechanical and biological factors.

Mechanical reasons

The aquarium is a closed ecosystem with many artificial details that recreate the natural habitat of fish. These include soil, decorations, roots, driftwood, ceramic pots, and coconut shells. All these objects contribute to the formation of solid suspended particles in the water, which lead to a significant decrease in the transparency of the water. The reason for this may be the overly active behavior of fish, many of which are prone to digging the soil and pulling out the roots of algae from it. , as well as improper maintenance of the decorations or improper start-up of the aquarium.

The last point is associated with a lack of experience among novice aquarists, who, having bought a new tank, fill it with untreated soil, set up decorations and pour water.

It is categorically impossible to do this. The soil should be selected for the fish that you plan to purchase. So, for some types of cichlids, for example, black-striped cichlases, it is recommended to use river pebbles as a soil. This is due to the tendency of the species to dig trenches, which is why, on the second day, an aquarium with a sandy bottom risks turning into a bowl with muddy and dirty water.

Therefore, before choosing a substrate, it is necessary to use special literature and get acquainted with the habits and characteristics of the life of those fish that you want to buy.

The next reason for the appearance of mechanical debris is the use of loose , soluble and coloring elements, which over time begin to deteriorate and cause water pollution. In this regard, you should not purchase too many decorations, which, although they decorate the aquarium, but under the influence of water, begin to deteriorate and cause it to become cloudy. Overcrowding of the reservoir and ineffective filter operation are often the cause of contamination. When choosing fish, it is imperative to take into account the size of the tank and remember that for every centimeter of the fish body there must be at least two liters of water.

As for the filter, it is better to purchase models that can distill at least two volumes of the aquarium per hour.

Biological causes

Contamination of the water in an aquarium is often caused by an imbalance in biological balance or biological balance. As known, aquarium water contains a huge amount of beneficial bacteria and fungi ... The former are involved in the processing of ammonia, nitrates and nitrites present in tap water, while the latter contribute to the decomposition of the remains of dead vegetation, converting organic compounds into inorganic ones, thereby maintaining biological balance.

Especially often new aquariums become cloudy, which is associated with the rapid growth of unicellular organisms and the simultaneous accumulation of fish waste products.

As a result, there is some discrepancy between the amount of biological waste and the number of microorganisms that process this biological waste. However, after a few days, the system self-regulates and the biological balance returns to normal. Fungi and bacteria begin to do their job perfectly, and the liquid becomes transparent. Usually, the balance is restored 3-5 days after launch, and the whitish fog dissipates without a trace.

As for the turbidity of the liquid in an old aquarium with an established ecosystem and a stable community, in this case, one of the most probable reasons is a violation of elementary care. For example, overfeeding fish leaves a lot of uneaten food, which sinks to the ground and begins to rot.

Finding fish in such conditions leads to a weakening of their immunity and can cause the death of the weakest members of the community.

Another biological factor causing water turbidity is algae. Some of their species, under the influence of excessive lighting, grow too much and provoke water bloom. In old aquariums, the biological balance is often disrupted by improper water changes. For example, replacing more than a third of the liquid from the total volume or inaccurate filling of a fresh portion, leading to the rise of solid suspensions from the bottom.

Chemical constituent

Along with mechanical and biological causes that cause cloudy water, there is also chemical pollution, which also leads to a change in organoleptic characteristics. This phenomenon often occurs after the use of aquarium medicines, which negatively affect not only pathogenic microflora, but also beneficial bacteria. As a result, the biological balance of the ecosystem is disturbed, and the aquarium liquid becomes cloudy.

What does the color say?

Seasoned aquarists are capable of unmistakably determine the cause of cloudy water by its color.

  • So, if the water darkens sharply and acquires green tint - this may indicate an excessive growth of microscopic algae. The reasons for this process may be an excess of sunlight or artificial light, ineffective filtering systems and poor-quality tap water. An equally common cause is clogging of the filter with debris and vegetation debris. In this case, it is enough to clean the unit and run it with clean water. To regulate the amount of microscopic algae, daphnia can be introduced into the aquarium, which will gladly devour them.
  • White dreg in an aquarium, it often appears from overpopulation of the reservoir, water changes by more than 1/3 and the treatment of fish with various chemicals. And also a whitish muddy shade often appears in newly launched aquariums, where the biological balance has not yet been established. In other words, the appearance of white turbidity indicates the struggle of the internal biological environment with poisons and toxic substances present in the aquarium water.
  • Brownish tint can appear as a result of an excess of wooden decorations, which over time begin to release tannin into the water. Such water does not pose a critical danger to fish, however, it spoils the appearance of the aquarium and makes it untidy. In addition, the acidity index changes, which can also negatively affect the general condition of overly fastidious fish species. To prevent the appearance of brownish turbidity, it is recommended to soak new wooden structures in water and keep them there for a while. Most of the harmful compounds come out in the first week, and decorative elements cease to be a source of brown dregs.
  • Liquid gray is the result of soil contamination or the presence of harmful elements such as silicates, heavy metals and phosphates in the water. To determine their presence and concentration, it is recommended to use special indicators or litmus tests, which show the level of their presence in water.

What does smell mean?

The smell appears a little later than the turbidity and is an indicator of more serious problems. The reasons for its appearance are still the same - it is insufficiently thorough and untimely care of the aquarium, poor filtration, overpopulation, insufficient oxygen saturation and incorrect selection of aquarium plants. Besides, the cause of the smell can be a dead fish, whose body decomposes and smells unpleasant .

If everything is in order with the filter and algae, all the inhabitants of the community are alive, and the smell has nevertheless appeared, you should pay attention to the food, since low-quality compounds often cause unpleasant odors. Another reason for the attenuation of water can be overfeeding of fish, as a result of which uneaten food sinks to the bottom, sours and begins to smell.

How to fight?

After the cause of the appearance of the turbidity is determined, you should immediately start to eliminate it. If the contamination was of a mechanical nature, then it is necessary to carefully siphon the bottom, remove all decorations from it and clean the walls of the tank from mucus and solid deposits. Next, you should carefully take 1/3 of the volume of water by adding fresh settled water. If the filter is very weak or too small for the aquarium, it is necessary to replace it with a more powerful model, taking into account the quantity and quality of aquatic vegetation, the size of the container and the total number of its inhabitants.

In order to quickly get rid of heavy contamination, experienced aquarists recommend replacing the sponge in a standard filter with a synthetic winterizer. It is placed in place of the removed sponge and the unit is turned on. This method helps to eliminate not only mechanical pollution, but also the greening of the aquarium liquid.

The first results will be visible after a few hours, and after another day the water will become completely transparent.

You can also get rid of mechanical water pollution with the help of activated carbon. It is put in a filter and left there for 2 weeks. This absorbent will quickly remove clouding and keep the water clear. However, activated carbon is incapable of absorbing nitrates and nitrites from liquid, therefore, it is additionally recommended to use zeolite.

If the turbidity of the aquarium water is associated with biological processes taking place in it, then to quickly restore the biological balance, they use specialized drugs that can inhibit harmful microorganisms and provoke the development of beneficial bacteria. These formulations also help neutralize the ammonia, nitrates and nitrites found in tap water.

Means to fight

In advanced cases, when the above methods are no longer effective, chemical preparations are used. They must be used in strict accordance with the instructions, having carefully read the composition and making sure that the components are well tolerated by all inhabitants of the aquarium. Modern industry produces a huge number of items of aquarium products , the most popular and effective of which are discussed below.

Tetra products are well known to Russian aquarists.

  • Crystal Water binds fine solids into tangible particles, which are easily captured by the aquarium filter. Already after 2-3 hours, the water in the tank becomes noticeably clearer, after 7-8 hours it becomes clean, and after another 10 hours it becomes crystal clear.

Professionals often use this drug on the eve of aquarium photo sessions, as well as before exhibitions.

  • Conditioning preparation Tetra Bactozym helps to accelerate the process of stabilization of biological balance in the ecosystem. Thanks to its use, the dissolved organic matter is enzymatically decomposed and does not pollute the water with decay products. In addition, the air conditioner helps to minimize damage from fluid replacement and filter flushing, as well as helps to recover microorganisms damaged by using medication.
  • Means-granules Tetra Nitrate Minus Pearls effectively reduces the nitrate content of the aquarium liquid and destroys some of the nutrients required by the algae for growth and development. The granules buried in the ground will allow you not to worry about the transparency of the water and not be afraid of the rapid growth of aquatic vegetation throughout the year.
  • Tetra Nitrate Minus Conditioner has the same effect as the previous drug, differs from it only in the form of release. It is represented by a liquid suspension, which is added weekly to the aquarium at the rate of 2.5 ml for every 10 liters of liquid. The drug converts nitrates into nitrogenous compounds, helps to normalize the carbonate hardness of water and stabilize acidity.

The following drugs are also very effective and work at a chemical level.

  • Sera Toxivec is engaged in blocking toxic compounds and is used as a preventive measure. However, it should be noted right away that this drug does not remove toxic substances, but only contributes to their transformation into forms that are safe for fish. It instantly neutralizes dangerous pollutants that threaten the health of the aquarium inhabitants and the life of beneficial bacteria. The drug quickly copes with ammonia and nitrites, does not allow them to turn into nitrates, and removes aggressive chlorine compounds from tap water.

In addition, it easily copes with the remains of disinfectants and drugs, binds mercury, zinc, lead and other heavy metals, and allows you to change the water in the tank a little less often than usual.

  • Sera Aquaria Clear acts by a biological method and binds any turbidity, regardless of its origin. The product does not contain harmful substances and is absolutely safe for the inhabitants of the aquarium.
  • Sera Bio Nitrivec is a tool that allows you to quickly start up the aquarium and restore the biological balance in it. Due to the presence of special bacteria in the composition, the fish can be launched within a day after filling the aquarium. The bacteria included in the preparation are instantly set to work, making the liquid clear and transparent.


Modern chemical and biological agents to combat fluid cloudiness are quick and effective, but in most cases they are used as a last resort. It is much better to prevent the formation of turbidity, in general, than to deal with its consequences later. For this a number of preventive measures must be taken to avoid contamination of the aquarium fluid and to keep all members of the aquatic community healthy.

  • Once a week, you need to replace part of the aquarium liquid, adding filtered and settled water. And also it is necessary to regularly clean the decor items, preventing them from overgrowing with green mucus.
  • It is advisable to feed the fish in such a way that all the food is eaten by them in 15-20 minutes. If the surplus food still remains and has already settled to the bottom, it is necessary to remove it from the substrate as soon as possible, without allowing it to sour and pollute the water.
  • The bottom soil should be regularly treated with an aquarium siphon, which will help protect the reservoir from cloudiness.
  • For self-cleaning of the aquarium ecosystem, it is recommended to purchase snails-coils, corridors, ancistrus, girinoheilus or algae-eaters, which feed on dead algae leaves and other organic matter, preventing it from rotting or blooming.
  • To improve water quality, it is recommended to use multi-stage filtration systems and purchase a phyto filter.
  • When starting new aquariums, it is advisable to add water from the old ones to them. This will help to quickly restore biological balance and will promote the speedy self-cleaning of the aquarium liquid.

For information on why the water in the aquarium becomes cloudy, see the next video.

654Clouding of aquarium water is a common occurrence, especially among novice aquarists.

In order to correct this situation, you need to understand the reason for the turbidity, then there will be no difficulty in solving the problem.

This article contains the most common causes of cloudy water in an aquarium, as well as what to do if this problem occurs.

What does the color of turbidity say?

Opacities come in a variety of colors. Color can explain the reason for these changes. Most often, the water becomes cloudy to green, brown, red or milky.

  • For instance, if the water in the aquarium is green , then most likely the reason is unicellular green algae that thrive in the aquarium. Such algae are absolutely harmless to fish, so you can fight them only for the sake of the aesthetic appearance of the aquarium.
  • 765The water can also be cloudy brown ... Most likely the reason is the snags, which are used as decoration. New driftwood releases tannin and humic acids into the water, staining it a dull brownish color.
  • Another option for the color of the water is red. ... The problem here is most likely the fish food. It is either of insufficient quality, or the aquarist overfeeds the fish, due to which the food particles remain uneaten, are crushed in water and stain the aquatic environment.
  • White dreg usually due to the fact that the environment contains a lot of bacteria and ciliates, which multiply in it. Typically, the water becomes cloudy white due to excess organic matter, which the filter is unable to cope with.

Why did it become cloudy?

What could this have come from? It is very important to understand the cause of the cloudiness, only then can the problem be dealt with.

Bacteria are the main cause

One of the most common reasons is bacteria, or rather their bloom. This phenomenon often occurs in newly launched aquariums, as it takes some time for the bacterial ecosystem to form. However, bacteria usually stop blooming after a few days.

Poor quality feed

Poor fish food dissolves quickly in the water, which prevents the fish from eating it. ... Because of this, the water becomes brown or reddish. Pellets by themselves take much longer to dissolve in water than flake foods, so they are best preferred. But there is also a good flake food for fish that will not spoil the aquarium's appearance, so you should try different types of food.

Excess food in fish

The quality of the feed can be high, but the water still becomes cloudy and discolored. This is due to the fact that the fish gorge themselves and do not eat all the food offered. After some time, any food begins to soak in water and "dust", therefore, the appearance of the aquarium becomes extremely unaesthetic.

Ground problems or improper maintenance

6543The aquarium environment can become cloudy due to the soil.

Light soil without sinking fraction is not able to settle to the bottom even a few days after the installation of the reservoir.

Such soil is deadly for all inhabitants of the reservoir. Also, the problem may be that the sand or soil is not rinsed well enough before filling it into the aquarium.


Green algae can multiply very actively due to which the water becomes cloudy and green. Excessive lighting can encourage algae growth and adding plant fertilizers. The absence of competitors in green plants (for example, brown or any other algae) leads to a very active growth of a certain species.

Overpopulation of the reservoir

There should not be too many fish in the aquarium. In this case, they can start digging through the soil or sand, which is why the water will be constantly cloudy. Also, the filter may not be able to cope with the water treatment of an overcrowded aquarium. Waste produced by fish will not settle or be treated properly, which can be fatal to the inhabitants of the reservoir.

Filter problems

Even if there is a filter, the water can become cloudy, so the filter for the aquarium must be designed for a certain volume of the tank. Otherwise, the filtration will be insufficient, which can cause the water to become cloudy, dirty and insufficiently saturated with oxygen. If the filter power is high enough, then the problem may be that the filter is clogged or not cleaned well enough.

Incorrect water change

If the water was changed incorrectly, then the environment in the reservoir may become cloudy. ... Water should not be changed too often or in large volumes.


water change

greatly reduces the population of beneficial bacteria, as a result of which their ability to process fish waste is reduced, and their place in the ecosystem is taken by other, useless blooming bacteria.

Replacing a large portion of the water can also affect the chemistry of the water, further reducing the beneficial bacteria population in the filter.

Poor decor elements

Some poor quality aquarium decorations can oxidize in the water, making the water cloudy. It is also possible that the paint will begin to peel off the decorative ornaments, or the dye will simply start to wash out. Such phenomena are dangerous not only from an aesthetic point of view, but can also harm fish and other aquarium inhabitants.

Poor and irregular care

8888999Aquariums need cleaning, water changes and fish and plant reproduction control.

Lack of proper care leads to the fact that the tank becomes dirty , the fish population is either increasing or decreasing, and algae can grow to the point that it interferes with other inhabitants of the aquarium.

Therefore, the life in the tank must be carefully monitored and controlled. Fish can die without proper care.

Unnoticed dead fish

Sometimes it happens that the aquarist does not notice the dead fish in the aquarium. Even a small fish can have a very powerful effect on the ecosystem of an aquarium.

What does the dregs talk about?

Cloudy water is just one of the symptoms that must be dealt with.

On the second day after the first launch

In a new aquarium, the water can become cloudy after start-up for several reasons. First of all, this can be due to the abundant multiplication of bacteria. In a new environment, bacteria multiply very actively to spread and occupy the entire territory. After a few weeks, the bacteria will stop multiplying so quickly and the water will clear up.

Also, in a new tank, the environment can become cloudy due to light particles of soil or sand that rise due to refilling of water or simply filling the tank.

The environment can become cloudy due to wood decor that has not been soaked for several days.

After substitution

The reason may also lie in the ground - if the stream of water is directed straight to the bottom, then the grains of sand rise, creating a visual impression of the cloudiness of the water.

New water can become cloudy due to multiplication of unicellular algae. After starting the reservoir, where the lighting is too bright and the aeration and filtration system is poorly adjusted, algae actively multiply, causing turbidity.

After restart

Once restarted, bacteria that are under stress can cause cloudiness. The problem may also be in insufficiently washed gravel or sand.

What does the smell say?

55667444Why does the water stink? The smell often appears a little later than the cloudiness, as a second sign of improper care. Let's consider the main reasons for which an unpleasant odor may occur:

  1. The most common cause of bad tank odor is insufficient care and maintenance.
  2. Also, the environment can smell unpleasant due to poor filtration or insufficient oxygenation.
  3. If the plants are incorrectly selected for the aquarium, this can also cause a bad smell.
  4. It is also worth checking if the body of a dead fish is left somewhere. The body begins to decompose and because of this, it smells unpleasant.
  5. Problems with the quality of the feed or overfeeding of the inhabitants of the reservoir also lead to the appearance of an unpleasant odor.
  6. Too many inhabitants in the aquarium - as a result, a musty smell from the tank.

How to deal with this?

So how do you eliminate the causes?

  1. In some situations, such as when starting the aquarium for the first time, it is better to do nothing at all. After a few weeks, the water will become clear.
  2. Sometimes it is necessary to replace partially or completely the water. Replacing the food or feeding the fish smaller portions can also help.
  3. If the water is painted from the decor, then it should be taken out and washed or soaked, and the aquarium water should be purified using activated carbon.
  4. Certain types of algae or snails can help purify the water.
  5. You should also clean the filter and make sure that it is powerful enough to purify the water and saturate it with oxygen.
  6. In some cases, a complete cleaning of the aquarium, followed by a water change, can help.


It is much better to avoid the appearance of turbidity than to deal with the consequences. To prevent such unpleasant phenomena, complex special actions are not needed.

It is enough just regular and careful maintenance of the tank: cleaning the aquarium, partial water changes, high-quality food. You need to carefully consider the choice of decor for the tank and filter, clean all the necessary elements in time ... Do not forget about the other inhabitants of the aquarium - snails and algae will be excellent helpers in the fight against cloudy water.

The most important thing in prevention is not to overfeed the fish. If this does happen, then you need to remove excess food from the bottom of the reservoir yourself. It is also important to regularly rinse the bottom filler with the aquarium siphon - this is a good preventive measure that will definitely protect the pond from cloudiness.

Related Videos

The video will tell you why the water can become cloudy:

Compliance with simple rules will allow you to never meet with such a problem as water turbidity. And if such a situation suddenly occurs, then it can be easily dealt with - it is enough to correct and establish proper care of the aquarium.

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Pet fish owners, who are simply underwater enthusiasts or professional aquarists, may occasionally encounter the problem of cloudy water in an "artificial reservoir". Why does the water in the aquarium become cloudy? How to deal with turbidity and how to avoid a similar problem?

Cloudy water in the aquarium: the main causes of the problem

Even a beginner in the aquarium hobby, when asked about water turbidity, will say that this problem arises from pollution in the "artificial reservoir". And he will be right. However, there may be several reasons for the appearance of turbidity in the reservoir, regardless of its size. And among them, one can single out key reasons, most of which require some action.

Why does the water in the aquarium become cloudy? Main reasons

  1. The presence in the "home reservoir" of small particles of soil, pollution, which are in suspension, thereby creating a muddy drag. A similar reason may arise due to improper soil cleaning, when new water is poured into the tank and if there are fish in the aquarium that live at the bottom and often break the existing sand. This foundation is harmless enough.
  2. Excess feed. It can both float inside the tank and sink to the very bottom. If the inhabitants of the "artificial reservoir" do not absorb the food that has settled down, it begins to rot, releasing phosphates. This leads to the following reason for the appearance of turbidity.
  3. Reproduction of bacteria inside the aquarium. They feed on food and waste products of aquatic inhabitants not eaten by fish. In some cases, when the colonies of bacteria of different species become excessively large, this reason for the turbidity of the water becomes negative, which must be dealt with. The same reason becomes the answer to the question why the water became cloudy and smells.
  4. Changes in the transparency of water due to nitrites and nitrates, which are the result of the life of aquatic inhabitants. When the aquarium is not cleaned properly or there are no special filters in the tank, this can also lead to cloudy water.
  5. Over-saturation of the "home reservoir" with fish and other underwater inhabitants. If there are ten fish in a small aquarium, an abundance of greenery and decorations, then this will lead to the rapid formation of a muddy drag. There is a rule: one medium-sized fish should have at least a liter of water.
  6. Lack of a purification system, filtration inside a home aquarium.
  7. Too frequent and complete change of water in the tank. The assumption that seemingly “spoiled” water should be completely replaced immediately, and that the aquarium itself and its inanimate contents should be thoroughly washed, is a delusion. Such measures will lead to disruption of the biological balance in the "artificial reservoir" and provoke the growth of bacterial colonies. As a result, the water will become even more cloudy.
  8. The appearance of algae in the aquarium. Algae of any order is considered a threat to the "home water". They grow very quickly, are prone to flowering, which is why the water loses its transparency and changes color. As a result, “black beard” algae, which are parasitic organisms, may appear inside the reservoir, and it can be difficult to get rid of them. Therefore, it is better not to bring the aquarium to such a state. In addition to turbidity, algae add an unpleasant odor.
  9. A change in the acid-base balance inside the reservoir, which occurs both due to the vital activity of bacteria, fish and other aquatic inhabitants, and due to the use of any chemicals that change the composition of the liquid.
  10. The water in the aquarium can become cloudy due to an excess of oxygen in it, which can also lead to the death of fish. In addition, too hard, chlorinated and unsettled water will look contaminated.
  11. Bringing new wood ornaments, such as sticks and small driftwood, into the “home pond”, can cause a sudden and abrupt clouding of the liquid in the tank. This is because the wood in the water releases tannins, tannins, which affect the purity of the contents in the aquarium. The presence of peat, as well as colored new pebbles, can also provoke turbidity.

How to identify the cause yourself and when to purify the water

A number of reasons for the appearance of cloudy water in an aquarium are not difficult to determine. A change in the color of the liquid in the reservoir will help to deal with more complex causes based on a bacterial factor or algae.

Four color options for contaminated water

If a question arises, why is the water getting dark , turns brownish , as shown in the photo below, the reason often lies in the abundance of wooden elements inside the "home reservoir".


Greenish tint , shown in the next photo, signals the excessive activity of algae. A characteristic wet-putrid smell from the surface of the water surface is added to the flowering.


Availability whitish tone indicates an increased activity of bacteria and ciliates, unicellular organisms. This can lead to the extinction of all fish and other inhabitants of the aquarium. And also provoke an unpleasant amber. An example of such turbidity is shown in the photo.


The fourth option can be the color of the water in the same tone with the ground or with numerous small multi-colored pebbles.

Purification of water will be required without fail in the second and third cases.

In a situation with brown haze, it is enough to get rid of the wooden element. And if the water in the aquarium becomes cloudy due to the soil, you need to wait a while, when its particles settle to the bottom by themselves. Or, extract the contents and rinse thoroughly under running water, washing out fine grains of sand.

In most cases, situations arise when cloudy water appears in a new aquarium. This is due to the fact that a biological equilibrium state does not yet exist inside the reservoir and the beneficial bacteria are very active. Fish should be launched into a new aquarium only 2-3 weeks after filling it with water. During this time, the liquid will independently take on a transparent state, especially if there is additional filtration in the aquarium.

How to get rid of muddy water: solutions to the problem

To get rid of the unfavorable reasons due to which there is a clouding of the liquid in the tank with fish, you can choose one or more of the methods given below.

  1. Carry out the resettlement of fish if their number significantly exceeds the permissible norm for the aquarium.
  2. Reduce the amount of dry food and get rid of uneaten food. It is useful to arrange a short diet for aquatic inhabitants, no more than 3 days. In a situation where it is surely known that it is the feed that affects the turbidity of the liquid, it is better to refuse to use dry powdered feed. Give preference to "live food" in the form of larvae of water mosquitoes and worms, which can be purchased in specialized stores.
  3. In addition to cleaning the soil and tank panes, it may be necessary to replace the vegetation inside the aquarium. Especially in cases where the greens are covered with an unpleasant film, there are darkening on it and a putrid smell emanates from it.
  4. To successfully purify muddy water, aquarium charcoal filters should be used. It will not be superfluous to bring the soil into a favorable form with the help of a special siphon.
  5. During the purification of opaque water, you should not replace all the liquid inside the "home reservoir" - this will not benefit the inhabitants. It is necessary to get rid of only 10-15% of the old water once every 2-3 weeks, replacing it with new one. The water in the aquarium can become cloudy after replacement either because of a large amount of fresh liquid, or because the added water was not settled, boiled and the temperature was strikingly different from the water in the tank.
  6. Enhanced oxygen enrichment will help to clear the cloudy liquid. However, you need to be careful about aeration so that small bubbles do not appear on the walls of the vessel with fish and on vegetation, decorative ornaments of the aquarium.
  7. To get rid of blooming algae, you need to reduce the amount of light directed to the “home pond”.
  8. In serious situations, coagulants can be used, which, in combination with the operation of the filters, will have a beneficial effect on cleaning. And also use special biofilters containing two types of bacteria inside. They are able to reduce the amount of nitrites and nitrates, phosphates in the aquarium water.

When in the "artificial reservoir" the water becomes cloudy, what to do, the video below will tell you:

In addition to the above methods of dealing with the turbidity of the liquid in the tank with underwater pets, you can resort to special products sold in zoological stores.

  1. "Tetra Crystal Water", cleans from any dregs.
  2. "8 in 1", a preparation that allows you to get rid of blooming and rapidly growing parasitic algae, destroys the green dregs in the water.
  3. "Sanex + EcoPrud", the product is intended not only for home aquariums. It also helps in the case of small bodies of water, ridding them of liquid contamination.
  4. Tetra AquaSafe is a conditioner that cleans turbid water, destroys pathogenic bacteria, and fights some fish diseases.
  5. API Algae Destroyer Advanced, another effective anti-algae treatment.
  6. Malachite Green is an antibacterial agent for home aquariums.

It is necessary to clean the cloudy water and the aquarium zone in general with the help of specially developed means at least once every six months. This will have a beneficial effect on the climate in the "artificial reservoir", save the fish from diseases and death, get rid of the accumulated ammonia inside the reservoir.

Additional information and recommendations

During the fight against whitish turbidity, it is worth refraining from replacing water, even in small quantities. The new fluid will provide additional nutrients to the growing bacteria colonies. Therefore, in this way, it will not work to purify turbid water.

When a new tank is started, you should add water from old aquariums to it. It will have a beneficial effect on the microclimate in the "home reservoir". The resulting cloudiness in this case will disappear after 3-5 weeks. Change the water in a new aquarium only after 3-4 months of use.

For effective natural water purification in an "artificial reservoir", it is worth adding several snails and daphnia (small crustaceans living at the bottom of the reservoir) to the fish. These underwater inhabitants successfully destroy food debris, eat algae and fight bacteria.

Additional recommendations

  • To prevent the liquid from acquiring a dark color due to the use of wooden elements, driftwood, twigs and other accessories for the aquarium should be thoroughly rinsed, and then soaked for at least a day.
  • When choosing soil for reservoirs in which goldfish live and species that prefer to swim close to the bottom, you should give preference to a soil layer with large granules. Fine river sand will create constant turbidity due to the activity of underwater pets.
  • Ordinary activated carbon can be added to the water, rather than using special charcoal filters.
  • Before chemical exposure, unless the instructions say about the complete safety of the product, fish and other inhabitants of the "home reservoir" must be deposited in a jar with clean water.
  • When dealing with overgrowing algae, it is not enough to simply cut back on artificial light. Protect the aquarium from direct sunlight.
  • Any filters must be regularly washed under a strong stream of running water.
  • From time to time, you need to conduct a home study, evaluating the amount of ammonia, phosphates, nitrates and nitrites in the composition of the water, which can affect its transparency. Special kits for this procedure can be purchased at pet stores.
  • When choosing a new aquarium, large tanks should be preferred. Their volume will allow faster development of internal biological equilibrium in water, due to which the initial turbidity of the liquid will also disappear faster.
  • It is worth regularly inspecting the reservoir with aquatic inhabitants and conducting an audit of the fish. Dead fish that are not removed from the aquarium on time decompose quickly. And this provokes the reproduction of pathogenic bacteria inside the "home reservoir".
  • Never fill the tank with tap water. It must first be defended for 10-14 days. If there is no time to wait, then you should cleanse the water from chlorine and other impurities with the help of neutralizing drugs sold in pet stores.
  • Too soft water, which does not contain any salts and magnesium, is unsuitable for aquarium fish. It is possible to reduce the hardness of a liquid, but not completely exclude it.

Competent fish care, including proper water purification, is troublesome and requires a lot of patience. However, following all the recommendations, taking into account the characteristics of the fish, it is so difficult to get rid of the cloudy water in the tank. This will make it easier for yourself to keep your underwater pets.

Almost every aquarist has had to deal with the phenomenon of cloudy water in the aquarium. It is dangerous to let this business take its course, you can lose aquatic life. To eliminate the problem, it is necessary to understand the reasons for the violation of the water biological balance.

What makes the water cloudy

The reasons for the turbidity of the water in the aquarium are associated with its improper arrangement, illiterate care of the aquatic environment or the natural life processes of microorganisms.

turbid water


The water can become cloudy temporarily, with further restoration of the water balance without human intervention. It is normal for a new tank to become cloudy on the second day after starting up. You should wait some time until the bacterial microflora is restored. For this reason, experienced aquarists never start fish right away, but wait 2-3 days. As soon as beneficial bacteria appear in the amount necessary for the water balance, the transparency will be restored.

It is useless to change the water as it will become cloudy again. To speed up the process of stabilizing the aquatic environment, when starting the aquarium, add some of the water from the old home reservoir to it.

Consequences of a water change

The presence of turbidity after a water change in the aquarium indicates that the procedure was not performed correctly. It is necessary to use hoses so that the fluid flow does not lift the suspension upward. There is a strict rule: you cannot change water by more than 1/3 of the volume. You cannot do this more often than once every 7 days. If you do not follow these recommendations, the water will become cloudy due to an imbalance in the biological balance.

Improper filter operation

Often the water in the aquarium becomes cloudy due to a broken or incorrectly working filtration system. A dirty filter element does not clean, but raises the dregs. If you tackle the filter and clean it well, transparency will be restored in a couple of days. You also need to correctly select the power of the device for the volume of the tank. If the problem persists after cleaning the filter, other causes of cloudiness should be considered.

Lost food

If the cause of the turbidity is improperly organized feeding, urgent action is needed. The fish are fed in such a way that the food is eaten in 5 minutes. Due to excess feed, the water quickly becomes dirty. It is absolutely impossible to overfeed the fish. The remnants of not eaten granules fall to the bottom of the tank, decompose and stink.

dirty water in the aquarium

Too many inhabitants

A cloudy aquarium with a characteristic ooze odor is a frequent occurrence in bodies of water that are inhabited by an exorbitant number of fish and shellfish. The filter device cannot handle the load. This is very dangerous for fish, as they can be poisoned, which will lead to death.

There will be no muddy water, if you correctly calculate the number of inhabitants - for every living organism with a body length of 1 cm, there should be at least 2 liters of water. Considering that the fish are growing, you need to leave a reserve.

Poor care

In the aquarium, a lot of waste products of its inhabitants are continuously generated. From this, the water will gradually deteriorate. If you abandon the fish habitat, do not care for it or do it illiterately, the mud in the aquarium is inevitable. Waste residues will decompose, smell bad, harmful microorganisms will spread through the reservoir.

Illiterately selected decorations

Decoration elements should be made of environmentally friendly materials insoluble in the aquatic environment. If the water has become cloudy, and also acquired an unusual color, most likely, the point is in chemical dyes.

Water quickly becomes cloudy from the use of paints, varnish, glue, loose substances of poor quality in the decor, which sooner or later will begin to dissolve and spoil the aquatic environment. Not only the aesthetic appearance of the decoration will suffer, but also aquatic inhabitants, who will have chemical poisoning.

Overgrown algae

Some types of algae are capable of multiplying at a tremendous rate. If the water becomes cloudy, a strong nitrogenous odor appears, most likely a matter of plants. The rapid growth of microscopic algae usually occurs in containers, which are exposed to direct sunlight, and where there is a large amount of organic matter. At the same time, a green tide appears near the water.

cloudy water in the aquarium

Unwashed soil

The water becomes cloudy if unwashed soil is poured onto the bottom when starting the aquarium. It is necessary to rinse to such a state until all small particles and dust come out. The water should become completely transparent.

How to determine the cause by color

What made the water cloudy can be determined by the color:

  • If the water in the aquarium is white, there are several reasons. But it all comes down to a violation of the biological balance. It will become whitish from the use of drugs, replacement of a large volume of water, overpopulation.
  • Green blooming water is a sign of microalgae proliferation. If, after changing the water, the aquarium was moved to another place, and the water still acquired a green color over time, it means that the biochemical balance of the system is seriously disturbed. Usually, this effect occurs when there is an excess of phosphates and nitrates.
  • Gray water is a consequence of a large amount of heavy metals, phosphates, silicates.
  • The brown color occurs when using wooden decorations. It is recommended to soak the driftwood for several days before submerging it in the fish habitat. Peat added to the filter device can give a brownish sheen.

Attention! It is recommended to have litmus strips or other indicators on hand to determine the acid-base balance in the aquarium at home. This will help eliminate problems in the aquatic environment.

Ways to eliminate turbidity

You can get rid of cloudy water in different ways:

  • It is necessary to clean the aquarium from waste products mechanically and to change the fourth part of the water volume. It is convenient to clean the soil using a special device - a siphon. Sometimes it becomes necessary to completely remove the soil and rinse it under a stream.
  • To resettle aquatic inhabitants if their number exceeds the norm for a given volume of the reservoir. It is necessary to take into account the number of not only fish, but also shellfish.
  • Reducing the light load by moving the aquarium to a darker location can slow down the growth of microscopic algae. The same effect can be achieved by changing the lamp to a less powerful one or raising it higher.
  • Sometimes it is enough to choose a more powerful filter or just to clean the filter element.
  • If after 5-10 minutes, as the feed was poured, it was not eaten, reduce the portion.
  • Intensive aeration of water helps to restore water balance. It is necessary to take into account which fish are inhabited. Not everyone can tolerate the movement of water. Aeration is more of a preventive measure.
  • You can quickly and effectively clean the aquarium from mechanical turbidity using chemicals.

In advanced cases, when substances hazardous to fish have entered the water, or decorative items have reacted with the aquatic environment, it must be completely changed.

Attention! The choice of a method for eliminating the problem depends on the cause that provoked this condition.

cloudy aquarium water

Cleaning with drugs

Special preparations that have absorbing properties help from mechanical turbidity in the aquarium:

  • Conventional activated carbon is good at picking up dirt and removing turbidity. First you need to clean it with a siphon. Then load coal into the filter compartment. Its effect lasts up to 14 days. Then it is removed. If necessary, load a second portion. Charcoal in a cotton bag can be immersed in the tank. The effect is the same.
  • Tetra CrystalWater helps to quickly remove the smallest dirt particles from the water. The result will be visible in 2.5 hours. After 6 hours, the water will become almost clear, after 12 hours it will become completely transparent. Usually, this drug is used before taking beautiful pictures of an underwater landscape.
  • Sera Aquaria Clear works in the same way, removes dregs of any origin in a short time. This substance is added to a special compartment of the filtering device. With its help, you can cleanse the water in the aquarium from turbidity without worrying about the well-being of the inhabitants. It is an environmentally friendly biological product.
  • The natural mineral zeolite, which belongs to the potassium group, is an excellent tool for cleaning the water in an aquarium. The stone is inexpensive, is a reliable and safe natural cleaner. Able to cope with the strongest pollution in artificial reservoirs. Reduces the concentration of ions and nitrates that are formed due to the functioning of the aquarium inhabitants.

On a note! Ions and nitrates provoke the active development of harmful microorganisms, due to which the water loses its transparency.

Prevention measures

It is less labor-intensive to prevent turbidity of the water space than to eliminate the consequences later. To avoid such a problem as turbidity in the aquarium, the following preventive measures are needed:

  • Thoroughly clean the substrate weekly with a siphon located at the bottom of the tank.
  • In a "mature" tank, carry out a partial water change every two weeks.
  • Equip the fish dwelling with a high-quality filtration and aeration system. It is desirable to add a zeolite mineral to the internal filtration. It should be borne in mind that excessively strong water flows from powerful devices can raise mud from the bottom.
  • Monitor the feeding rate of fish and the quality of feed.
  • Avoid overpopulation by aquatic inhabitants of the indoor reservoir.
  • Do not introduce plant fertilizers into the soil unnecessarily. Micronutrient oversaturation leads to turbidity and increased microalgae growth.
  • Maintain the correct temperature regime. Bacteria multiply in superheated water. The water will bloom and cloudy.
  • As a soil, it is advisable to choose not sand, which can give suspension, but small pebbles.
  • Use a special aquarium cover that prevents dust and dirt from getting inside.
  • Periodically use special conditioners for the transparency of the water according to the instructions, without exceeding the recommended dose. They are sold in specialized stores where products for aquariums are sold.

These measures will help to reduce the content of suspended solids and bacteria that create a cloudy effect.

Aquarium water doesn't darken for no good reason. To eliminate the danger to aquatic life, it must be found and eliminated. Often the fault of negative changes in the aquatic environment is a careless attitude to the hygiene of the aquarium. If you pay due attention to this issue, you can reduce the problem to a minimum.

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Biological water treatment

Biological water purification includes the most important processes occurring in closed aquarium systems. By biological purification we mean mineralization, nitrification and dissimilation of nitrogen-containing compounds by bacteria living in the water column, gravel and filter detritus. Organisms performing these functions are always present in the thickness of the filter. In the process of mineralization and nitrification, nitrogen-containing substances pass from one form to another, but nitrogen remains in the water. Removal of nitrogen from solution occurs only during denitrification (see section 1.3).

Biological filtration is one of four ways to purify water in aquariums. Three other methods - mechanical filtration, physical adsorption and water disinfection - are discussed below.

The water purification scheme is shown in Fig. 1.1., And the nitrogen cycle in the aquarium, including the processes of mineralization, nitrification and denitrification, is shown in Fig. 1.2.

 Place of biological treatment in the process of water treatment

Fig. 1.1. Place of biological treatment in the process of water treatment. From left to right - biological cleaning, mechanical filtration, physical sedimentation, disinfection.

The nitrogen cycle in closed aquarium systems

Fig. 1.2. The nitrogen cycle in closed aquarium systems.

1.1 Mineralization.

Heterotrophic and autotrophic bacteria are the main groups of microorganisms that live in aquariums.

Note not from the author's book.

Heterotrophs (other Greek - "different", "different" and "food") - organisms that are not able to synthesize organic matter from inorganic by photosynthesis or chemosynthesis. For the synthesis of organic substances necessary for their vital activity, they require exogenous organic substances, that is, those produced by other organisms. During digestion, digestive enzymes break down polymers of organic substances into monomers. In communities, heterotrophs are consumers of various orders and decomposers. Almost all animals and some plants are heterotrophs. According to the method of obtaining food, they are divided into two opposed groups: holozoic (animals) and holophytic or osmotrophic (bacteria, many protists, fungi, plants).

Autotrophs (other Greek - itself + food) - organisms that synthesize organic substances from inorganic ones. Autotrophs make up the first tier in the food pyramid (the first links in the food chain). They are the primary producers of organic matter in the biosphere, providing food for heterotrophs. It should be noted that sometimes it is not possible to draw a sharp boundary between autotrophs and heterotrophs. For example, the unicellular algae euglena green is an autotroph in the light, and a heterotroph in the dark.

Sometimes the concepts of "autotrophs" and "producers", as well as "heterotrophs" and "consumers" are mistakenly identified, but they do not always coincide. For example, blue-green (Cyanea) are capable of producing organic matter themselves using photosynthesis, and consuming it in finished form, and decomposing it into inorganic substances. Therefore, they are producers and reducers at the same time.

Autotrophic organisms use inorganic substances from soil, water and air to build their bodies. In this case, carbon dioxide is almost always a source of carbon. At the same time, some of them (phototrophs) receive the necessary energy from the Sun, others (chemotrophs) - from chemical reactions of inorganic compounds.

Heterotrophic species utilize organic nitrogen-containing components of the excreta of aquatic animals as a source of energy and convert them into simple compounds, for example, ammonium (the term "ammonium" refers to the sum of ammonium (NH4 +) and free ammonia (NH3) ions, determined analytically as NH4-N ). Mineralization of these organic substances is the first stage of biological treatment.

Mineralization of nitrogen-containing organic compounds can begin with the degradation of proteins and nucleic acids and the formation of amino acids and organic nitrogenous bases. Deamination is a mineralization process during which an amino group is cleaved to form ammonium. The subject of deamination can be the cleavage of urea with the formation of free ammonia (NH3).

Keeping fish in closed systems S. Spott

Such a reaction can proceed in a purely chemical way, but the deamination of amino acids and their accompanying compounds requires the participation of bacteria.

1.2. Water nitrification.

After organic compounds are converted into inorganic form by heterotrophic bacteria, biological purification enters the next stage, called “nitrification”. This process is understood as the biological oxidation of ammonium to nitrites (NO2-, defined as NO2-N) and nitrates (NO3, defined as NO3-N). Nitrification is carried out mainly by autotrophic bacteria. Autotrophic organisms, in contrast to heterotrophic ones, are capable of assimilating inorganic carbon (mainly CO2) to build the cells of their body.

Autotrophic nitrifying bacteria in freshwater, brackish water and saltwater aquariums, they are mainly represented by the genera Nitrosomonas and Nitrobacter. Nitrosomonas oxidizes ammonium to nitrite, and Nitrobacter oxidizes nitrite to nitrate.

Keeping fish in closed systems S. Spott

Both reactions take place with energy absorption. The meaning of equations (2) and (3) is to convert toxic ammonium into nitrates, which are much less toxic. The efficiency of the nitrification process depends on the following factors: presence of toxicants in water, temperature, content of oxygen dissolved in water, salinity and filter surface area.

Toxic substances ... Under certain conditions, many chemicals inhibit nitrification. When added to water, these substances either inhibit the growth and reproduction of bacteria, or disrupt the intracellular metabolism of bacteria, depriving them of their ability to oxidize.

Collins et al. (1975, 1976) and Levine and Meade (1976) reported that many antibiotics and other fish treatments did not interfere with nitrification in freshwater aquariums. while others turned out to be toxic to varying degrees. Parallel studies in seawater have not been carried out, and the results presented should not be generalized to marine systems.

The data given in the three indicated works are presented in table. 1.1. The results of the studies are not entirely comparable due to differences in the methods used.

Table 1.1. Influence of therapeutic norms of dissolved antibiotics and medicinal products on nitrification in freshwater aquariums ( Collins  et  al ., 1975, 1976, Levine  and  Meade , 1976).

Influence of therapeutic norms of dissolved antibiotics and medicinal products on nitrification in freshwater aquariums

Collins et al studied the effects of drugs in water samples taken directly from operating biofilter pools containing fish. Levine and Mead used pure bacterial cultures for their experiments. The methods used by them, apparently, were distinguished by higher sensitivity in comparison with the usual ones. Thus, in their experiments, formalin, malachite green, and nifurpyrinol had moderate toxicity for nitrifying bacteria, while Collins et al. Demonstrated the harmlessness of the same drugs. Levine and Mead believed that the discrepancies were associated with a higher content of autotrophic bacteria in pure cultures and that the inactivation threshold would be higher in the presence of heterotrophic bacteria and at a higher concentration of dissolved organic matter.

From the data table. 1.1. it can be seen that erythromycin, chlorotetracycline, methylene blue and sulfanilamide have pronounced toxicity in fresh water. The most toxic among the studied substances was methylene blue. The results obtained when testing chloramphenicol and potassium permanganate are contradictory.

Collins et al and Levine and Mead agree that copper sulfate does not significantly inhibit nitrification. Perhaps this is the result of the binding of free copper ions with dissolved organic compounds. Tomlinson et al. (1966) found that heavy metal ions (Cr, Cu, Hg) have a much stronger effect on Nitrosomonas in pure culture than in activated sludge. They suggested that this is due to the formation of chemical complexes between metal ions and organic substances. Long-term exposure to heavy metals is more effective than short-term, apparently due to the fact that the adsorption bonds of organic molecules have been fully used.

Temperature ... Many types of bacteria can tolerate large fluctuations in temperature, although their activity is temporarily reduced. The adaptation period, called temporary temperature inactivation (TTI), often occurs with sudden changes in temperature. Usually VTI is noticeable when the water is suddenly cooled; an increase in temperature, as a rule, accelerates biochemical processes and therefore the adaptation period may go unnoticed. Srna and Baggaley (1975) studied the kinetics of nitrification processes in marine aquariums. An increase in temperature of only 4 degrees Celsius led to an acceleration of the oxidation of ammonium and nitrite by 50 and 12%, respectively, compared with the initial level. With a decrease in temperature by 1 degree Celsius, the rate of ammonium oxidation decreased by 30%, and with a decrease in temperature by 1.5 degrees Celsius, the rate of nitrite oxidation decreased by 8% compared to the initial conditions.

pH of water ... Kawai et al. (Kawai et al., 1965) found that at pH less than 9, nitrification in seawater is more suppressed than in fresh water. They attributed this to the low natural pH in fresh water. According to Saeki (1958), ammonium oxidation in freshwater aquariums is suppressed with decreasing pH. The optimum pH for ammonium oxidation is 7.8 for nitrite oxidation is 7.1. Seki considered the optimal pH range for the nitrification process to be 7.1-7.8. Srna and Baggali showed that marine nitrifying bacteria were most active at pH 7.45 (range 7-8.2).

Oxygen dissolved in water ... A biological filter can be compared to a huge breathing organism. When properly operated, it consumes a significant amount of oxygen. The oxygen requirements of aquatic organisms are measured in units of BOD (biological oxygen demand). The BOD of a biological filter is partially dependent on nitrifiers, but mainly due to the activity of heterotrophic bacteria. Harayama (1965) showed that a large population of nitrifiers was active at high biological oxygen consumption. He passed seawater through a layer of sand of an active biological filter. Before filtration, the oxygen content in the water was 6.48 mg / l, after passing through a layer of sand 48 cm thick. it dropped to 5.26 mg / l. At the same time, the content of ammonium decreased from 238 to 140 mg equiv / l, and nitrites - from 183 to 112 mg equiv / l.

The filter layer contains both aerobic (O2 is needed for life) and anaerobic bacteria (does not use O2), but aerobic forms prevail in well-aerated aquariums. In the presence of oxygen, the growth and activity of anaerobic bacteria are suppressed, so the normal circulation of water through the filter inhibits their development. If the oxygen content in the aquarium decreases, there is either an increase in the number of anaerobic bacteria, or a transition from aerobic respiration to anaerobic respiration. Many products of anaerobic metabolism are toxic. Mineralization can also occur at a reduced oxygen content, but the mechanism and end products are different in this case. Under anaerobic conditions, this process is more like enzymatic than oxidative, with the formation of organic acids, carbon dioxide and ammonium instead of nitrogenous bases. These substances, along with hydrogen sulfide, methane and some other compounds, impart a putrid odor to the choking filter.

Salinity ... Many species of bacteria are able to inhabit waters, the ionic composition of which fluctuates significantly, provided that changes in salinity occur gradually. ZoBell and Michener (1938) found that most bacteria isolated from seawater in their laboratory can be grown in freshwater. Many bacteria have even undergone direct transplantation. All 12 species of bacteria considered exclusively "marine" were successfully transferred to freshwater by gradual dilution with seawater (5% fresh water was added each time).

The bacteria in the biological filter are very resistant to fluctuations in salinity, although if these changes are large and sudden, bacterial activity is suppressed. Srna and Baggaley (1975) showed that an 8% decrease in salinity and an increase of 5% did not affect the rate of nitrification in marine aquariums. Under normal water salinity in marine aquarium systems, the nitrifying activity of bacteria was maximum (Kawai et al., 1965). The intensity of nitrification decreased both with dilution and with an increase in the concentration of the solution, although some activity persisted even after the water salinity increased by half. In freshwater aquariums, bacterial activity was at its highest before the addition of sodium chloride. Immediately after the salinity became equal to the salinity of sea water, nitrification stopped.

There is evidence that salinity affects the rate of nitrification and even the amount of finished products. Kuhl and Mann (1962) showed that nitrification was faster in freshwater aquarium systems than in marine aquariums, although more nitrite and nitrate was formed in the latter. Kawai et al. (Kawai et al., 1964) obtained similar results, which are shown in Fig. 1.3.

Filtration bacteria count in small freshwater and saltwater aquarium systems after 134 days 

Figure: 1.3. The number of bacteria in the filtration layer in small freshwater and marine aquarium systems after 134 days ( Kawai  et al ., 1964).

Filter surface area ... Kawai et al. Found that the concentration of nitrifying bacteria in the filter is 100 times higher than in the water flowing through it. This proves the importance of the size of the filter contact surface for nitrification processes as it allows bacteria to adhere. The largest surface area of ​​the filter bed in aquariums is provided by gravel (soil) particles, and the nitrification process takes place mainly in the upper part of the gravel pack, as shown in Fig. 1.4. Kawai et al. (1965) determined that 1 gram of sand from the top layer of the filter in marine aquariums contains 10 bacteria in the 5th degree - ammonium oxidants 10 in the 6th degree - nitrate oxidants. At a depth of only 5 cm, the number of microorganisms of both types was reduced by 90%.

Concentration and activity of nitrifying bacteria at different filter depths in a marine aquarium

Figure: 1.4. Concentration (a) and activity (b) of nitrifying bacteria at different filter depths in a marine aquarium ( Yoshida , 1967).

The shape and size of the gravel particles are also important: fine grains have a larger surface for bacteria to attach than the same amount by weight of coarse gravel, although very fine gravel is undesirable because it makes water filtration difficult. The relationship between size and surface area is easy to demonstrate with examples. Six cubes weighing 1 g. They have a total of 36 surface units, while one cube weighs 6 grams. Has only 6 surfaces, each larger than a single small cube surface. The total area of ​​six one-gram cubes is 3.3 times the surface area of ​​one 6-gram cube. According to Seki ( Saeki , 1958), the optimal size of gravel (soil) particles for filters is 2-5 mm.

Angular particles have a larger surface area than rounded ones. The ball has the smallest surface area per unit volume compared to all other geometric shapes.

Detritus accumulation (The term "detritus" (from Latin detritus - worn out) has several meanings: 1. Dead organic matter temporarily excluded from the biological cycle of nutrients, which consists of the remains of invertebrates, secretions and bones of vertebrates, etc. small undecomposed particles of plant and animal organisms or their excretions suspended in water or settled on the bottom of the reservoir) in the filter provides an additional surface and improves nitrification. According to Seki, bacteria that inhabit detritus account for 25% of nitrification in aquarium systems.

1.3. Dissimilation

The nitrification process results in a high oxidation state of inorganic nitrogen. Dissimilation, "nitrogen respiration", or the reduction process, develops in the opposite direction, returning the end products of nitrification to a low oxidation state. In terms of total activity, the oxidation of inorganic nitrogen significantly exceeds its reduction, and nitrates accumulate. In addition to dissimilation, which ensures the release of a part of free nitrogen into the atmosphere, inorganic nitrogen can be removed from the solution by regularly replacing part of the water in the system, due to assimilation by higher plants or using ion exchange resins. The latter method of removing free nitrogen from solution is applicable only in freshwater (see section 3.3).

Dissimilation is a predominantly anaerobic process that takes place in oxygen-deficient filter layers. Bacteria - denitrifiers that have a regenerative ability, usually either complete (obligate) anaerobes, or aerobes capable of switching to anaerobic respiration in an oxygen-free environment. As a rule, these are heterotrophic organisms, for example, some Pseudomonas species, can reduce nitrate ions (NO3-) under conditions of oxygen deficiency (Painter, 1970).

During anaerobic respiration, dissimilating bacteria assimilate nitric oxide (NO3-) instead of oxygen, reducing nitrogen to a compound with a low oxidation number: nitrite, ammonium, nitrogen dioxide (N20) or free nitrogen. The composition of the final products is determined by the type of bacteria involved in the recovery process If inorganic nitrogen is completely reduced, that is, to N2 Oor N2, the process of dissimilation is called denitrification ... In a fully reduced form, nitrogen can be removed from water and released into the atmosphere if its partial pressure in the solution exceeds its partial pressure in the atmosphere. Thus, denitrification, in contrast to mineralization and nitrification, reduces the level of inorganic nitrogen in water.

1.4. Balanced aquarium.

A “balanced aquarium” is a system in which the activity of bacteria inhabiting the filter is balanced with the amount of organic energetic substances entering the solution. By the level of nitrification, one can judge about the "balance" and suitability of the new aquarium system for keeping aquatic organisms - aquatic organisms. In the beginning, the high ammonium content is the limiting factor. Usually, in warm water (above 15 degrees Celsius) aquarium systems, it decreases after two weeks, and in cold water (below 15 degrees) - over a longer period. The aquarium may be ready to receive animals within the first two weeks, but it is not quite balanced yet as many important groups of bacteria have not yet stabilized. Kawai et al. Described the composition of the bacterial population of the marine aquarium system.

1. Aerobic. Their number in 2 weeks after the fish was planted increased 10 times. The maximum number is 10 to the eighth degree of organisms per 1 g. Filter sand - marked two weeks later. Three months later, the bacterial population stabilized at the level of 10 to the seventh degree specimens per gram. Sand filter.

2. Bacteria that decompose protein (ammonifiers). The initial density (10 to the 3rd degree ind./gr) increased 100 times in 4 weeks. After three months, the population stabilized at a level of 10 to the 4th degree ind./gr. Such a sharp increase in the number of this class of bacteria was caused by the introduction of feed (fresh fish) rich in protein.

3. Bacteria that decompose starch (carbohydrates). The initial number was 10% of the total number of bacteria in the system. Then it gradually increased, and after four weeks began to decline. The population stabilized after three months at 1% of the total bacterial count.

4. Nitrifying bacteria. The maximum number of bacteria, oxidizing nitrites, was noted after 4 weeks, and "nitrate" forms - after eight weeks. After 2 weeks, there were more "nitrite" forms than "nitrate" ones. The number has stabilized at the level of 10 to the 5th degree and 10 to the 6th degree of specimens. respectively. There is a time difference between the decrease in the ammonium content of the water and the oxidation at the beginning of nitrification, due to the fact that the growth of Nitrobacter is inhibited by the presence of ammonium ions. Effective oxidation of nitrite is only possible after most of the ions have been converted by Nitrosomonas. Similarly, a maximum of nitrite in solution should appear before nitrate accumulation begins.

The high ammonium content in a new aquarium system can be caused by instability in the numbers of autotrophic and heterotrophic bacteria. At the beginning of the work of the new system, the growth of heterotrophic organisms exceeds the growth of autotrophic forms. A lot of ammonium formed during mineralization is assimilated by some heterotrophs. In other words, it is impossible to clearly distinguish between heterotrophic and autotrophic ammonium processing. Active oxidation by nitrifying bacteria appears only after the reduction and stabilization of the number of heterotrophic bacteria (Quastel and Scholefield, 1951).

The number of bacteria in a new aquarium only matters until it stabilizes for each type. Subsequently, fluctuations in the supply of energy substances are compensated by an increase in the activity of metabolic processes in individual cells without increasing their total number.

In the studies of Quastek and Sholefild (1951) and Srna and Baggaliy it was shown that the population density of nitrifying bacteria inhabiting a filter of a certain area is relatively constant and does not depend on the concentration of incoming energy substances.

The overall oxidative capacity of bacteria in a balanced aquarium is closely related to the daily intake of oxidized substrate. A sudden increase in the number of reared animals, their weight, the amount of feed applied leads to a noticeable increase in the content of ammonium and nitrite in the water. This situation persists until the bacteria adapt to new conditions.

The duration of the period of increased ammonium and nitrite content depends on the magnitude of the additional load on the processing part of the water system. If it is within the maximum productivity of the biological system, equilibrium in the new conditions in warm water is usually restored after three days, and in cold water - much later. If the additional load exceeds the capacity of the system, the ammonium and nitrite content will continually increase.

Mineralization, nitrification and denitrification - the processes that take place in a new aquarium more or less consistently. In an established - stable system, they go almost simultaneously. In a balanced system, the ammonium (NH4-N) content is less than 0.1 mg / l, and all nitrites captured are the result of denitrification. These processes are coordinated, without lagging, since all incoming energy substances are quickly assimilated.

This material is an excerpt from S.Spott's book "Keeping fish in closed systems", in full it is presented by the link - here.

Any aquarium is a closed ecological system. And if cloudy water appears in the aquarium, then urgent measures should be taken to eliminate the causes, since this can cause the death of its inhabitants.

Cloudy water in the aquarium

Causes of cloudy water in the aquarium

Clouding can be caused by both mechanical and biological causes. The first results from:

  • non-compliance with the standards of caring for fish and invertebrates;
  • mistakes made by novice aquarists when starting;
  • using unsuitable decorations.

Violation of biological balance occurs as a result of the death of beneficial microorganisms and the predominance of pathogenic flora.

Types of cloudiness in the aquarium

Experienced ichthyologists will have no difficulty in determining the appearance of the reason why the water in the aquarium becomes cloudy.

The vessel acquires a green color due to the rapid reproduction of the algae in it. Their explosive growth causes excess illumination. The water can turn green due to rotting feed and dead leaves, resulting in a characteristic odor. Experts recommend putting planktonic crustaceans and daphnia into the reservoir to correct the situation, the latter are deposited a day after the water is purified. In winter, artificial lighting should be used no more than 10 hours a day, in summer - no more than 12, and even more so, direct sunlight should not be allowed.

The best ecological solution to the problem of algae growth is to plant a hornwort in the aquarium, which absorbs excess nitrogen, thereby preventing unwanted euglenide growth.

Another factor that the liquid acquires an emerald hue is the increased content of phosphates. They accumulate due to special additives in fish feed and then end up in excrement. Tap water can also be saturated with phosphates. To combat this, fast-growing plants should be planted, and special conditioners in the form of tablets should be used as chemicals for cleaning the environment, which do not pose any harm to the inhabitants of the aquarium.

Yellow contamination is due to several reasons:

  • improper care of fish;
  • improperly selected food;
  • insufficient filtration or its absence;
  • selection and use of cheap decorations and snags.

To prevent yellowness, you need to buy quality products, turn off the internal cleaner during feeding. You can replace one third of the old volume of liquid with settled fresh water, the same temperature as in the tank.

White haze occurs after replacing an old substance with a new one, or after the first start of the aquarium, or due to excessive organic matter in the water. As a result, the bacteria start to release too much nitrite. Experts consider this manifestation to be normal, since all animals and plants must begin to create biogenesis again, which usually takes 2 weeks. After this time, the water will become clear again. Therefore, one should refrain from replacing it, otherwise the process will be repeated again.

To accelerate cleansing, various Tetra conditioners are used.

The liquid foams in both long-used and newly launched aquariums. The reason for the formation of foam in old tanks is improper care, irregular cleaning of the walls, contamination of working filters. All this can be easily avoided by observing the rules of keeping and feeding residents. Bubbles on the surface will pass into new ones by themselves, as soon as the nitrites, ammonia and nitrates released by aquatic inhabitants during the formation of symbiosis evaporate.

The formation of a film coating on the water surface indicates:

  • the presence of fatty feed;
  • poor movement and mixing of the water mass;
  • accumulation of microscopic algae.

Among the reasons, experts point out the wrong selection of decorative materials for aquariums, the use of cheap food. In order to eliminate the problem, it is recommended to launch ampularia snails into the ecosystem.

If these measures do not bring the desired results, then the help of aquarists will be needed.

Mr Tail recommends: the main reasons

The most common causes of cloudiness in an aquarium are:

  • excessive overfeeding of its inhabitants;
  • incorrectly selected soil and feed;
  • vital activity of parasites;
  • overcrowding and other factors.

Let's consider each of them in more detail.

Excess food causes uneaten ingredients to settle to the bottom and begin to rot, and the reservoir smells bad. As a result, there is a danger to the life of the inhabitants of the reservoir. Therefore, if nutrients remain on the surface 15 minutes after feeding, they are removed.

Untreated soil also causes unwanted darkening processes. Before placing it inside, wash the substrate thoroughly until the drained water becomes clear.

The quality of the food is directly reflected in the condition of the aquarium water. Flake food decomposes faster, so it is advisable to buy it in pellet form.

Bacteria begin to multiply actively, usually immediately after filling a new or old aquarium. According to ichthyologists, this process is natural, therefore, it is better to start the fish in a new environment the next day after changing the water - during this time without nutrition, the bacterial environment will die. If you change the liquid in an old tank, then the water that was in it before is recommended to be stored in a separate container and added in parts to speed up the process of cleaning from turbidity, if necessary.

Due to overcrowding, the fish begin to dig through the soil, constantly raising the suspended matter and particles settling in it. As a result, there is an additional load on the filter, which does not have time to purify the water and becomes clogged. When choosing purifiers, one should also take into account the fact that manufacturers produce them for a certain volume of liquid, so this parameter should not be neglected when buying devices. A weak filter cannot clean large reservoirs.

Elodea in the aquarium
Elodea for cleaning

Clogged materials and improperly selected decor elements also cause turbidity. Decorations made of low-quality materials begin to oxidize, and some have a violation of the external integrity, cheap dyes are washed into the aquarium water and pollute it.

Along with all the factors, one more is essential - improper care. It is necessary to monitor the number of fish, avoiding overcrowding. Before launching new species, it is necessary to consult with specialists how they will harmoniously combine with the old ones, and how much water is needed for the life of each individual. Usually three liters are used for 1 fish.

What to do if the water in the aquarium is cloudy

After analyzing the causes, you can proceed to measures to eliminate them for the normal functioning of the aquarium ecosystem:

  • If the turbidity is associated with overfeeding, then the fish are satisfied with a three-day diet, and in the future it is recommended to change the powder food to worms and insect larvae, which are sold in pet stores. If there is no possibility of switching to natural ingredients, then bottom fish should be settled in the reservoir, which, feeding on particles that have settled down, will improve the condition of the water.
  • Decayed, damaged and covered with a film of algae are removed, the walls and soil are washed. Siphons are used to clean sand, and special charcoal filters are used for water. To combat the excessive growth of algae, sidex is used.
  • If overcrowded, fish should be resettled.
  • Many novice aquarists, when the water becomes cloudy, strive to immediately get rid of the liquid, but this should never be done. Ichthyologists recommend replacing up to 15% of the old water volume with new water once every two to three weeks or weekly. In this case, the portion to be added should be settled and the same temperature as the aquarium water.
  • To prevent algae from blooming, the tank should be protected from direct and prolonged light.
  • As one of the methods for purifying the liquid, active saturation of it with oxygen is used. In this case, it is necessary to avoid the appearance of bubbles on the walls, decorations and algae.
  • If none of the above measures has given the desired result, special coagulants and biological filters are used, inside of which there are two types of beneficial microorganisms that reduce the content of nitrates, nitrites and phosphates in the aquarium liquid.
  • A natural purifier is the aquatic plant Elodea serrata. It is unpretentious, does not emit much oxygen and at the same time can serve as green food for fish.
  • Pet stores sell special conditioners designed to curb the growth of algae and neutralize the waste products of harmful microorganisms, discoloration of the liquid.
  • The drug Bicillin-5, sold in pharmacies, can also be used to combat the resulting cloudiness. Before pouring the medicine into the container, all inhabitants are moved to another container. And the drug is added to the contaminated water for three days without a break. If this period is not enough, then cleaning continues for another week.

How to prevent the appearance of turbidity

In order for the water not to acquire unpleasant shades, you should follow the elementary rules for keeping aquariums and their inhabitants at home:

  • before starting, it is necessary to wash the glasses and the bottom substrate, disinfect the decorations;
  • do not save on filters, do not neglect the norms of water purification by them;
  • all new decorative elements must be thoroughly cleaned before immersion in the container;
  • constantly monitor the condition of the soil and replace it as it gets dirty;
  • do not overfeed the inhabitants;
  • remove dead plants and animals in a timely manner.

Many of us keep pets. However, some people are allergic to them. In this case, you can set up an aquarium with fish at home, which do not have any negative effect on the body. However, there are no less problems with them - if you feed them the wrong way, they will die. Or the water will start to cloud. Why? Today we will analyze this problem in more detail.

Why does the water in the aquarium become cloudy?

Causes of cloudy and greening of water

This can happen for a variety of reasons, and it is far from always possible to effectively deal with them. One thing is clear - tiny algae, bacteria or particles of solids have appeared in the water.

  • If this happened immediately after you filled the aquarium with water, it is likely that the cloudiness was due to uplifting. There is no need to be afraid of this, the dregs after some time will sink to the bottom by itself. Especially often this phenomenon can be observed in reservoirs where veil-tails, goldfish, cichlids and other aquatic animals, digging the ground in search of food, live.
  • If the water in the aquarium is not filtered and not blown through, and there are very few plants, then the accumulated metabolic products become a favorable environment for the development of many bacteria. The water becomes cloudy due to the fact that ciliates and other unicellular bacteria begin to multiply in it, which, by the way, are harmful to both fish and plants. The reason for their appearance is simple - it is either too many fish in the occupied area, or their excessive feeding. Remember that it is better not to feed your pets than to overfeed, as food leftovers will serve as a breeding ground for bacteria. If the tank is small, then you can try to transplant the fish. In extreme cases, you can stop feeding for 2-3 days - the bacteria will disappear, and nothing will happen to the fish. And of course, do not forget to clean the tank of debris and food debris.
  • Experts say that cloudy water is also possible in the first few weeks - bacteria multiply here again, but in this case they disappear after two to three weeks after adaptation.
  • Greenish water can also indicate the growth of algae rather than bacteria, but in this case, it is more difficult to establish the true cause of the problem. Vegetable bloom is most often observed due to an excess of light in the room. Try to temporarily exclude sunlight from entering the aquarium, and also limit the duration of artificial lighting.
  • However, the matter may not be at all in the light, but in the overabundance of nitrates or phosphates, due to which the active growth of algae begins. They can only enter the tank from water or from the food that you feed the fish with. If the problem lies in tap water, then it will need to be replaced, and if it is in food, you will need to underfeed your "aquatic pets" for some time.
  • What else? Often the reason lies in the use of chemicals that tend to change the pH. For example, the owner of the aquarium did not dissolve these substances before adding them to the water. The worst thing is that the fish can suffer, so it is recommended to transfer them to a tank with clean water so that they do not get poisoned.
  • If the water turns gray or slightly white, you probably didn't wash the gravel well. It must be rinsed until the water becomes crystal clear. Also, a similar shade is possible if heavy metals or phosphates are present in the water. In this case, it must be replaced.
  • Water becomes brownish due to various wooden objects or if it is filtered through a layer of peat. How can you avoid this? Before diversifying the aquarium with new driftwood, be sure to soak them first. They secrete humic acids and tannin, which are generally safe for fish, although occasionally they can cause poisoning. You can also try to replace the water several times or add activated carbon to it - with its help the dyes are absorbed.
  • But other colors can appear as a result of adding various drugs to the water or, say, gravel of unusual colors. In both cases, activated carbon can help.
  • Sometimes the cause of this phenomenon is a suspended matter. This can be dirt, for example, from decorative objects, suspension that the filter cannot handle, food particles (by the way, the latter are eaten up only by snails), dead fish that have begun to decompose.

What to do?

First you need to find out the reason for the change in the color of the water in the aquarium, and then proceed to eliminate it. A little higher, we have already written what actions need to be resorted to in each individual case. Recall, however, that in order to maintain the aquarium and maintain the biological balance in it, it is imperative to use a filter, otherwise water will instantly get dirty. Also, do not forget to add special additives to it. It is also recommended to settle snails or such fish in the aquarium that will eat up the excess of accumulated vegetation.

How often should the water in the aquarium be changed?

Remember that changing water plays a very important role in the life of your pets. If you do this too often, or vice versa very rarely, then the fish may simply not stand it and die after a while. Therefore, in order to find out exactly when it is necessary to change the water in your aquarium, you need to contact a specialist.

However, there are general rules. Firstly, after the first start of water, it is not recommended to change it for the first two to three months, so that equilibrium would be established. Then replacement should be done approximately every 20-30 days up to one fifth of the total volume of the reservoir. If you have a high-quality filter, and there are few fish, then the water needs to be changed even less often. If you do this often, then the pets can simply die.

And remember - you must follow all the rules for caring for fish from the very first minutes after buying them - this will save you from many problems in the future.

What made it cloudy in the old and in the new, what is the difference?

foto21396-2It is normal for a new tank to become cloudy when the ecosystem has not yet stabilized.

It takes time for a biological balance to be established in it. when microorganisms are eaten by the inhabitants of the aquarium, and only the amount of bacteria is formed, which is necessary to maintain natural processes.

In an old aquarium, dregs cannot appear just like that. And if this happens, it will not pass on its own until the reason is found out and measures are taken.

What does the smell of the swamp say?

There are 6 reasons why the aquarium might start to smell:

  1. Irregular care. For beginners, the signal to clean is an unpleasant smell. The longer you delay cleaning the aquarium, the more disgusting it will smell.
  2. Insufficient filtration (lack of oxygen).
  3. Wrong selection of plants.
  4. The uncleaned body of a dead fish or snail.
  5. Overfeeding of the inhabitants (the appearance of an excessive amount of feces or fish disease due to overeating).
  6. A large number of "residents". The feces do not have time to decompose, forming a concentrated, foul-smelling mass.

Removing the swamp smell is simple: wash the aquarium and change the water. But if you do not find out the reason, the next wash is coming in a week.

How to deal with clouding?

For instant cleaning from turbidity, you can use special tools:

  1. foto21396-3Chemical. For example, conditioners for aquarium water Crystal Water Tetra Aqua, Sera Aquaria Clear, Formamed, AquaCons.

    They really help cleanse the water from the turbidity, making it crystal clear.

  2. Folk. Someone prefers to add activated carbon to the filter. It not only retains dirt particles, but also disinfects water. Another option is to place foam sponges or microfiber cloths in the filter.

These funds do not fight the cause of the appearance of turbidity, but only temporarily eliminate it. It is impossible to use chemistry all the time, so you need to find out the cause of the turbidity.

What are the reasons and how to eliminate them?

Let's assume that the reason for the cloudy water in the aquarium is determined. It remains to take appropriate measures.


A large amount of fish waste products make the water not only cloudy, but also toxic. Feces contain phosphates and ammonia that are harmful to the inhabitants of the aquarium.

Therefore, the daily amount of food poured into the aquarium should be calculated based on the number and type of inhabitants.

How to feed your fish properly to get rid of cloudy water:

  • foto21396-4it is advisable to pour the feed into the restrictor feeder so that the granules do not spread over the surface of the water and do not decompose, creating additional turbidity;
  • if it is not possible to calculate the dosage, you need to track how much feed the fish eat at a time and add less the next time;
  • the food should not be taken with your fingers: you need a special spatula that will help you determine the dosage and rid the aquarium of excess bacteria living on human skin.

It is best to choose pelleted feed because the flakes decompose faster.

Sometimes the fish overeat so much that they begin to spit food. This also makes the water cloudy. The measures are the same - to calculate the dosage.


Turbidity is formed for the same reason: excess faeces. How to get rid of it:

  1. Calculate the number of inhabitants of the aquarium based on the displacement - the required volume for one individual.
  2. Move excess fish and crustaceans to another aquarium.

Rotting plants

The decay process can be determined visually:

  • leaves and stems become soft,
  • are covered with bloom,
  • bend and shrink.

They are slimy and unpleasant to the touch. Cause: Unsuitable plant for the aquarium or lack of lighting.

What to do:

  • foto21396-5remove plants that are not intended for aquariums;
  • unscheduled wash the filter and add water to clear it of mucus;
  • check the lighting system: the light must hit the entire space inside the aquarium;
  • check the oxygen tube: flush it or replace the aerator;
  • choose special underwater plantings.

Ground problems

Ideally, the bottom of the aquarium should be lined with fine pebbles and coarse sand. Too small particles (suspension) constantly float up due to the activity of the inhabitants, making the water cloudy.

What to do:

  1. "Vacuum" the soil to remove the suspension.
  2. Remove the old soil and introduce a new one, after rinsing it with running water to get rid of dust.

If the turbidity does not always appear (for example, with excessive activity of the fish), it is enough just to wait a few minutes. Small particles will settle, and the water will become visually clear again.

Irregular care

This can also lead to cloudiness. It is advised to thoroughly wash the aquarium no more than once a year. But cleaning should be done weekly. This is done with clean hands:

  1. foto21396-6Walls. Plaque and algae are removed with a scraper with a sponge at the end. You do not need to moisten the sponge with detergents.
  2. Priming. An excellent tool is a soil cleaner. This is a kind of water vacuum cleaner that sucks up feces and settled particles of feed from the ground.

    If the soil is sandy, you need to keep the pump at a distance of 3 cm from it so as not to draw in the sand.

  3. Scenery. Fish houses, pebbles and other equipment are taken out of the aquarium and washed under running water.
  4. Filter. It is turned off from the network, taken out, disassembled and washed under running water. Additionally, you can rub especially dirty items with a brush. Be sure to replace the dirt barrier sponge.
  5. Cap. Wipe clean with a damp cloth or remove and rinse with running water. It's the same with lighting fixtures.

A change (draining 15-30% of old water and refilling with fresh water) is carried out approximately once a month. The water is completely drained only if none of the above measures helps, and the turbidity does not disappear.

When cleaning the aquarium, do not use any detergents. An invisible film from them remains on the walls or on the decorations, even if you rinse them very carefully. For fish and crustaceans, this is destructive.

Poor quality water

foto21396-7If all of the above does not help, then the problem is in the water.

For an aquarium, you need to prepare it in advance: pour into a clean container and stand for 6 hours .

You also need a good filter, which should be regularly cleaned of adhering dirt particles. Can't cope alone? You can install the second one or replace the first one with a more powerful one. This will ensure the transparency of the aquarium and the safety of its inhabitants.

What to do for prevention?

Preventive measures to maintain aquarium cleanliness are to follow the basic rules for keeping fish.

You must first read the literature, and then choose the inhabitants and quality food for them. , which should be poured with a measuring spoon at the specially designated time. It is also necessary to change the water on time and monitor the number of individuals in order to remove the corpses in a timely manner.

Sometimes the water becomes cloudy in especially responsible owners. Therefore, do not take out the decorations from the aquarium once again in order to rinse them.

You do not need to enter an additional day of cleaning and scrape off the plaque that has just formed from the walls. It is not necessary to use the ground cleaner every day. Because the mud in the water is not only harmful, but also beneficial bacteria that are necessary to maintain the ecosystem.

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Why the water in the aquarium becomes cloudy, the video will tell you:


Cloudy water is not a reason to sound the alarm and seek professional help. But this is a signal that the ecosystem may not be all right. Timely elimination of the problem will allow you to enjoy beautiful fish swimming in a clean aquarium.

Nitrogen cycle

The fish in the aquarium lay down waste, the faeces sink to the bottom of the aquarium and begin to break down. In this case, ammonia (NH3) is formed and deposited, which is bad, since it is indeed toxic. If enough ammonia builds up, it will chemically burn the gills of the fish and eventually they will die.

Fortunately, there are different types of good bacteria that colonize the filters and help recycle fish waste. One group of bacteria converts ammonia to nitrite (NO2-), and another group converts nitrite to nitrate (NO3-). Nitrates are much less toxic than ammonia and nitrite, so you can let them build up a little between water changes.

Ammonia and nitrite levels at 1ppm can stress and kill fish. In contrast, nitrates can be safely maintained at 40 ppm, but ideally should be kept at 20 ppm.

The aquarium has white or gray muddy water

The gray water in the aquarium looks like a glass of milk has been poured into it. The water is still clear, but there is a thick haze that makes everything look fuzzy. There are also extreme cases when the fish is almost impossible to see. There are several reasons for the appearance of gray water.

New substrate

If the substrate is not rinsed out enough, it will turn into a huge cloud and create a lot of mess.

If new gravel, sand or soil has just been added to the aquarium, a cloud of dust or detritus may be trapped in the water column.

Substrate bags are moved, tossed, and mishandled as they travel from manufacturer to store. All this movement leads to the fact that the substrate inside the bag rubs against itself and breaks off tiny particles that form fine dust.

How to eliminate cloudy water due to a new substrate

Polyester fiber

Sufficient patience is required to correct water that has become cloudy due to the new substrate. It may take only a few hours, but in some cases the process may take several days.


  • Change water 50% and try to remove dust.
  • Add an ultra-fine mechanical filter material capable of capturing fine particles. Polyester fiber is a great option.
  • Rinse the substrate.

The easiest way to rinse the substrate is by placing small amounts in a bucket and pumping water from a garden hose through it until the water runs clear. It is especially important to do this with plant substrates because they can cloud the water to such an extent that the fish cannot be seen.

Best results are obtained using a sink hose at very low flow. Buckets can be used by slowly pouring water into the tank. Yes, it will take forever, but there will be fewer problems with it.

Blooming bacteria

If the water has turned milky and the owner hasn't just added a new substrate, he may face a much more serious problem - bacterial bloom.

Bacterial bloom occurs when an explosive growth of heterotrophic bacteria (bacteria that require organic compounds for food) occurs in the water column. Individual bacteria cannot be seen with the naked eye. But when there are billions of them, you can actually see their giant swarm clouding the water.

They are different from the beneficial bacteria that process ammonia. The beneficial bacteria in the filters are autotrophic (they can feed on inorganic substances). Heterotrophic bacteria cause fish waste to rot and form ammonia.

Heterotrophic bacteria do not infect or cause disease in fish. As a rule, they are constantly present in all aquatic environments, just hanging out in the background. But their numbers can skyrocket when there is a lot of organic waste in the water that they can eat.

This can be caused by:

  • Overfeeding. The bacteria feed on uneaten food in the aquarium.
  • Overpopulation. Too many fish for the volume of the aquarium.
  • Insufficient filtration level for a particular aquarium and / or number of fish.
  • Excessive cleaning of the filter and the destruction of colonies of beneficial autotrophic bacteria that live in them.
  • Dead fish in the tank.

Although bacteria do not directly cause disease in fish, they can negatively affect water quality and cause disease in fish. Many people think that bacterial blooms are caused by ammonia emissions because they often see cloudy water and elevated ammonia levels at the same time.

Ammonia release does not cause bacterial bloom. The bacteria bloom causes the release of ammonia. The swarm of bacteria eats the dissolved organic matter and dumps tons of waste in the form of ammonia.

How to deal with bacterial blooms

Bacterial bloom most often occurs when the aquarium has not accumulated enough beneficial bacteria to process fish waste.

Here's how to deal with it:

  • If there is no fish in the aquarium - for example, if the owner starts the cycle without fish, there is no need to do anything about the bacterial bloom. You just have to let it take its course, and it will disappear as soon as the heterotrophs eat the organic matter and die.
  • With fish in the aquarium - since these bacteria can deplete oxygen in the water, it is important to increase aeration.
  • Monitor ammonia levels daily ... Continue testing ammonia and taking steps to combat it.

How to prevent gray water from returning

The best way to prevent this problem from recurring is to remember the importance of regular aquarium maintenance.

These actions include:

  1. Regular water changes ... A weekly water change of 25% -50% removes organic waste from the water. Be sure to use a gravel vacuum cleaner and remove dirt from the substrate.
  2. Rinse the filters with water from the reservoir ... It is recommended to clean the filters about once a month. You do not need to sterilize them, this will kill the necessary and beneficial bacteria, but you can wash off the sludge that has accumulated over time.
  3. Sponges and filter inserts can also cause serious odor. ... Washing and squeezing them in a bucket of dechlorinated water can remove waste that would otherwise just settle and break down in the filter.

Correct filter maintenance not only helps to get rid of nitrates, but also prolongs the filter's life.

Yellow / brown water

Sometimes the aquarium water can take on a yellow-brownish tint. It is caused by the tannins in the water. There is no need to panic about this at all. Tannins will not harm fish or plants.

They are produced by plants as a defense mechanism. They give the plants a strong bitter taste, which helps prevent insects from eating them.

In an aquarium, driftwood is the most common source of tannins, although in some areas tannins are found in local tap water.

How to prevent yellow / brown water

There are several ways to prevent tannins from staining the water:

  1. Pre-soak anything that can release tannins in the aquarium water. For example, a new piece of driftwood should be soaked in a bucket or plastic container of salt water for several days. Mix ½ cup of aquarium salt with 3.5 - 4 liters of water. It is necessary to plan wood soaking for at least 3-7 days. If the water begins to resemble iced tea, it must be emptied and replaced. When the water remains clear for 24 hours, it's time to put the driftwood in the tank.
  2. If really large pieces of driftwood are added to the aquarium, they can leach out tannins over time, no matter how long they have been soaked.
  3. It is best to use activated carbon or another form of chemical filtration. The use of chemical media will remove tannins from the water as they form.

The water in the aquarium turns green

Green water looks exactly as it sounds, it actually turns bright green. Don't worry, green water isn't bad for fish, it just looks awful.

Green water is caused by microscopic algae blooms. These microalgae float freely in the water column.

There are three main components that cause almost all types of algae to bloom. If the owner can handle this, the unpleasant shade can defeat.

  1. Shine ... Either too much light is being used, or the light stays on for too long. Generally, the best way to combat algae is to control the light.
  2. Nitrates ... They accumulate in the water column, if the owner forgets to change the water, then algae thrive on it.
  3. Phosphates ... This is another nutrient that algae really love. This is somewhat of a steroid for algae.

How to adjust lighting

Lighting control is usually the easiest way to get rid of green water and keep it out. The owner should try to keep the aquarium from direct sunlight from the windows. Natural light enhances algae growth.

You really only need to turn on the lights for 8-10 hours a day. Reduce the light to a minimum first. Once the algae are under control, you can try gradually increasing the time.

By turning on the timer, you can control how long the light burns each day without effort.

How to reduce and regulate nitrate levels

There are several ways to control nitrate levels in your aquarium:

  1. Do not overfeed ... Eaten food decomposes and releases tons of nitrates and phosphates. It is worth feeding the fish only what they eat, in about 30 seconds (2-3 minutes for slow eaters). Even if they ask for more, they really don't need it.
  2. Monitor maintenance ... Again, constant cleaning of the aquarium and filters will reduce nitrate levels. Less nitrate means less fuel for algae and other microorganisms in the aquarium.

How to reduce and regulate phosphates

Use the water phosphate test

Any organic compound that degrades in the aquarium deposits phosphate (PO4): dead fish, dead plant material, uneaten food, fish waste.

Some pH control chemicals are also phosphate based, and some fish feed companies use phosphate as a preservative.

To control phosphate levels, you need to:

  • Do not overfeed fish.
  • Change the water regularly.
  • Remove dead fish and plant material from the aquarium immediately.
  • Do not use chemicals containing phosphate.

Bad smell

A well-maintained aquarium is unlikely to ever develop a strong odor, as unpleasant odors usually arise from the decomposition of biological material (biowaste) that has not been treated.

Here are some sources of biowaste:

  • Dead fish ... The most common cause of unpleasant odors in the aquarium is dead fish. It may take several days after the death of a fish before the owner realizes that something is wrong. The timely discovery of the body and its removal should eliminate the odor.
  • Excess food ... Overfeeding is another common cause of bad odor in aquariums. The uneaten food falls to the bottom of the container, where it promotes the growth of bacterial colonies. As bacteria grow exponentially, they release foul-smelling waste gases.
  • Waste from an overfilled tank ... Excessive amounts of biowaste can also be the result of overcrowding. Overflowing an aquarium means too many fish are living in too little water. When a fish eats, it excretes excrement. The more fish, the more faeces. Eventually, the excess waste becomes too much for filters and beneficial bacteria.
  • Decomposition of plants ... Although less common, a rotting plant can give off a horrible odor even under water if left unattended. Fortunately, dead plants are easy to spot. They often turn slimy brown or black and spoil water quality.
  • Dirty and Smelling Aquarium Filter Cushion ... In fact, there is often more rotting sludge in the filter than in the aquarium itself. After all, the job of a mechanical filter is to collect in one place any debris that floats in the aquarium.
  • Water conditioner added during the change can also cause a strange odor from the aquarium. It is best to avoid using water conditioners with an unpleasant odor, such as sulfur, which is often the cause of the rotten egg smell.
  • If the odor coming from the aquarium smells like rotten eggs, the substrate may be to blame. ... Sand or very fine gravel that has compacted over time can form zones where oxygen is not available. When waste gets into these pockets, bacteria turn it into gases. A deep gravel vacuum or regular sand mixing can prevent these gases from building up in the aquarium. And before choosing a substrate for your aquarium, you need to read how to care for it!
  • Seashell and instead of pebbles. They rot in fresh water and give off an unpleasant odor.

How to fix the problem

The first thing to do is to conduct a thorough ongoing fish inventory. If any are missing, start looking for the remains, as this could be the cause of the foul smell.

Sometimes the fish is eaten by their aquarium mates, so the missing fish may never be found, but predation does not smell.

If the decaying body of the fish is not the source of the odor, and all fish are present and accounted for, then the problem is most likely due to the accumulation of organic material in or on the gravel.

In this case, you need:

  • Find plant remains and uneaten food particles.
  • Use a vacuum cleaner or scoop to clean the substrate inside the tank.
  • It is good to clean the entire tank and then reduce the feeding regimen to one small feed per day.
  • It will also be necessary to clean the filter before and after the cleaning process. If there is a lot of debris in the tank, this indicates that the filter is likely clogged and has been poorly filtered for a while. After eliminating all sources of unpleasant odor, perform the odor test again.

Prevent cloudy and bad smelling water from forming in the tank

There are a few key steps to take to prevent cloudy or foul-smelling water from reoccurring in your tank:

  • Avoid overfeeding your fish, as any uneaten fish food will simply settle to the bottom of the aquarium and break down into waste, providing bacteria and algae with the nutrients they need.
  • Do not forget about regular weekly water changes - change from 10% to 20% of the volume of the aquarium weekly and be sure to pump out some of the aquarium substrate during each water change.
  • Replace filter material monthly. Adding activated charcoal filler or activated charcoal pads to the filter will help purify the water and adsorb the nutrients that feed the bacteria bloom.
  • "Seed" the aquarium. If the owner has access to another healthy, well-established aquarium, a few handfuls of gravel from that aquarium can be added to sow beneficial bacteria and speed up the cleaning process. Specialist shops sometimes keep filter cartridges and bio-sponges floating in filled aquariums to inoculate them with bacteria.
  • Check the aquarium water for ammonia and nitrite. In most situations, the levels will be zero, which means there is no cause for concern.

Thus, there are several reasons for problems with cloudy water and unpleasant odor. Fortunately, they can be easily eliminated with a little research and finding out what factors influenced this phenomenon.

Video tips on how to solve the problem of cloudy water in the aquarium

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