In the amateur hobbyist circle, the term “water quality” means the amount of water polluting agents — toxins and organic compounds, although, strictly speaking, if the chemical composition of water and its gas content are not suitable for fish living in it, it is believed that such water also has inadequate quality.
Contaminants may have a different origin. They can get into the water from some sources, come from the decoration or equipment of the aquarium, from the home environment, they can produce plants, fish and other fauna in the aquarium.
Contaminants present in tap water
Tap water suitable for humans may contain chemicals that are toxic to fish. The most common substances are:
Chlorine. This gas is usually added to the water supplying companies for the purpose of disinfection.
A high concentration of chlorine can be determined by the characteristic smell of this gas, familiar to many people who have visited swimming pools. It can be withdrawn as follows: you need to put a strong stream of water in the bucket (however, note that if after this “treatment” there is still a smell of gas, it is better to use another method) or leave the water in the bucket overnight with intensive aeration; alternatively, a patented dechlorinator can be used.
Chloramine. This is a mixture of chlorine and ammonia, used by some water utilities instead of simple chlorine. (Chloramine can also be formed independently as a result of the interaction of chlorine from tap water and ammonia contained in aquarium water. The compound is persistent, nonvolatile, and rather toxic. – Note from the consultant.) Information about this can and should be obtained from the above-mentioned enterprises.
Chloramine can only be removed with a special dechlorinator specifically designed to remove both ammonia and chlorine.
Copper. Under natural conditions, it can get into the water from the soil or stones containing copper salts, and in the home – from the aqueduct, especially in those areas where the water is soft and the calcium carbonate protective coating does not form. Before filling the aquarium, first open the tap for a few minutes to drain the water that is stagnant in the pipes, and in no case pour water from the tap with hot water into the aquarium.
If the water contains natural pollutants, including copper, use a special means to remove copper (it can be purchased at pet stores), or pass water through a reverse osmosis unit, or use water from another source.
Nitrates and phosphates. Sometimes they are contained in tap water that has been contaminated by agricultural fertilizers or wastewater and not properly treated. Both nitrates and phosphates can be removed using reverse osmosis.
In pet stores you can buy special reagents for the removal of nitrates. Alternatively, you can use another water source.
Pesticides These may be traces of agricultural activity or chemicals used by water utilities in order to destroy the pathogenic flora and fauna that live in the water supply network. To determine the presence of copper and nitrates in water, special tests (indicators) can be purchased.
Pesticides can be removed using reverse osmosis or use another source of water.
The aquarist should ask the water company to let him know when they plan to use pesticides in the water supply network, and seek their advice on how long he will have to wait before the water becomes safe for the fish again. Water companies sometimes spread the printed results of the analysis of the water supplied by them to the area, and this information can also be useful.
Using rainwater may seem like an ideal option to avoid problems such as hardness and excessive alkalinity, but this is fraught with danger. Rainwater is almost always acidic, because atmospheric carbon dioxide is dissolved in it, which forms highly diluted carbon dioxide.
However, in areas with heavy industrial pollution, rainwater may contain sulfur compounds that form sulfuric acid in dangerous concentrations (sulfur showers). Other toxic substances from the polluted atmosphere can also be dissolved in rainwater.
To a certain extent, this can be avoided if water is collected only during a heavy downpour accompanied by wind, and the collection of water should begin approximately 30 minutes after it starts, when the air is already clear.
Rainwater can also be contaminated due to contact with roofing materials, gutters and pipes, dirt and debris (including such as leaves, bird nests, drowned chicks and insects, etc.). The water collection container itself, unless it is made of a material inert to water, can also cause pollution.
Finally, rain water should be filtered immediately after collection to remove all debris, store it in a non-toxic container, and filter again before use through a carbon filter.
Chemical pollution of water in the aquarium due to aquarium equipment
This usually happens if stones or soil containing toxic substances are used in an aquarium. In addition, poorly processed snags, the use of detergents, poorly washed after special treatment elements of the aquarium design, the use of equipment not intended for aquaristics (especially metal or plastic items), and unsuitable types of glue, varnishes and paints.
Pollutants entering the aquarium from the home environment
The result of this type of contamination is usually rapid and fatal poisoning. Typical causes of contamination are as follows:
Aerosols and other dispersed substances – for example, insecticides, polish for furniture, household cleaners.
Smoke or fumes from oil or paraffin heaters, varnishes, paints, cigarettes.
Organic waste produced by the flora and fauna of the aquarium
All living things, both animals and plants, produce organic waste. This waste can be produced either during the life of organisms as products of metabolism (excretion, carbon dioxide) and discarded dead tissue (skin cells, leaves), or as a result of decomposition of the organism after death.
Under natural conditions, this waste passes through a repeated cycle, participating in biological processes. The most important of these processes is the nitrogen cycle; it also occurs in the aquarium.
Understanding the essence of the nitrogen cycle, during which bacteria of certain species process waste products of living organisms, is vital for the successful maintenance of healthy fish. In fig. The main features of this cycle and the impact they have on the aquarium are presented.
The bacteria involved in this process colonize the aquarium soil, and also live in a biological filter. The filter’s function is to increase the biological activity, to enrich the habitat space of bacteria necessary for the nitrogen cycle with oxygen.
Ammonia and nitrites are extremely toxic to fish, but if the nitrogen cycle passes correctly, these toxic substances will turn into relatively harmless nitrates before their concentration reaches a dangerous level. It should be noted that the nitrogen cycle will take place in any aquarium, and not only where biological filtration of water is applied.
However, in the new aquarium the nitrogen cycle will not start until the aquarium itself or its biological filter “matures” properly. Therefore, the fish should not be launched into the aquarium until such “maturation” is completed. The fact is that in the aquarium just flooded with water there are no necessary populations of bacteria participating in the nitrogen cycle, and at first there the contents of extremely poisonous ammonia will sharply increase, which will contribute to the development of bacteria that process ammonia into nitrites (also very poisonous).
This, in turn, will lead to a sharp increase in nitrite content. Finally, the time will come when bacteria that convert nitrites to relatively harmless nitrates also form a large enough population.
That’s when the aquarium finally becomes safe for fish. This whole process continues for several weeks. (The nitrates themselves are low toxic, but if you do not monitor their concentration, the reverse transition of nitrates to nitrites will begin. – Approx. Consultant.)
A population of bacteria is able to quickly compensate for small fluctuations in the “amount of work” (that is, the amount of waste to be recycled). However, a large overload caused, for example, by the appearance in the aquarium of dead fish or overfeeding of fish, can lead to a temporary sharp increase in the content of ammonia and nitrite. The simultaneous appearance of a large number of new fish in an aquarium can also lead to similar results.
To avoid this, an aquarist must take some precautions. Initially, the fish should be fed gradually, and then over a week or more gradually increase the amount of feed and finally bring it to a normal level.
Then the beneficial bacteria will have enough time to multiply and cope with the increased load.
To measure the content of ammonia, nitrite and nitrates, special tests are used, which should be part of the basic equipment available to each aquarist. Even experienced specialists sometimes have problems with an abundance of organic matter.
These problems usually manifest themselves as signs of fish being unwell. If you always have the necessary tests at hand, this problem will be able to identify and get rid of it before it can do any significant damage.
Partial water change
There are often more fish and fewer plants in an aquarium than in the same amount of water in nature. In addition, in the aquarium there is no constant renewal of water due to rains and the flow of rivers. Therefore, although it is theoretically possible to achieve an equilibrium in which all nitrates produced from the waste products of fish will be consumed by plants, in reality this is practically unattainable.
In such a “perfect” aquarium there must be very few fish, and for most aquarists this is far from ideal. In addition, there are aquariums in which there are no plants at all.
All this means that without the intervention of an aquarist, the level of nitrates in the water will gradually grow and slowly but surely cause health problems in fish. If you run a new fish in the aquarium, where the level of nitrate content is higher than in the aquarium to which they are accustomed, the fish will experience nitrate shock, which could even lead to their death.
In addition, high levels of nitrates can trigger the rapid development of algae.
We have already discussed how to use special equipment to remove nitrates from water coming from one or another source. However, this is not the optimal method for removing nitrates from an aquarium. Instead, it is better to control the level of nitrate content by regularly replacing part of the water in the aquarium with a new one.
At the same time, nitrates and other undesirable impurities (for example, chlorine) must be removed from the new water before it is added to the aquarium. A low concentration of nitrates in the water source is acceptable if their content in the aquarium is kept within safe limits. In addition, a partial replacement of water allows you to restore stocks of essential minerals.
The influx of fresh water usually causes increased activity in fish.
Before adding fresh water to the aquarium, it is necessary to bring its chemical composition and temperature in accordance with the chemical composition and temperature of the water in the aquarium. Such measures will avoid the risk of such phenomena as pH shock, temperature shock and gas embolism.
The frequency of water changes and the volume of water replaced can be different for different aquariums and depend on a number of factors, mainly on the density of fish and plant populations in relation to the volume of water, as well as on the number and type of fish feed offered. You can replace no more than one-third of water at a time (except for critical cases, such as serious poisoning).
For a start, it would be good to replace once a week from one-fifth to one-fourth of the water, while checking the level of nitrates. In some areas, especially in drought conditions, it is advisable to measure the level of nitrate content in it each time before adding tap water to the aquarium, as in such conditions a seasonal increase in this level may be observed.
Filtration is another important part of maintaining good water quality. Various types of aquarium filters are available. In most cases, the filter is a container filled with special materials of one or several types.
These materials are called filter media and are used to trap solid particles (mechanical filtration), provide habitats for bacteria performing the nitrogen cycle (biological filtration), or change the chemical composition or quality of water (chemical filtration). Literally all aquarium filters and filter materials act as mechanical ones, and most of them, in addition, also function as biological filters.
For chemical filtration, a special filtering material is required, which at the same time ensures the action of a mechanical or biological environment. Aquarium water is pumped through the filter so that the filtering material contained in it can fulfill its purpose.
This is the release of water from suspended solids (fish excrement, pieces of dead leaves) and their removal from the aquarium. Thanks to the mechanical filtration, the aquarium looks clean and the water becomes clear. It is extremely important to understand that the waste nevertheless always remains part of the aquarium system, since the aquarium water constantly circulates and repeatedly passes through the filter.
Therefore, they can still cause water pollution with ammonia, nitrite and nitrate. A filter clogged with uneaten food is almost as dangerous as rotting food left on the ground, but many aquarists do not attach due importance to this fact.
The filter can only be used to mechanically collect waste, but in this case it should be cleaned regularly – at least once a week so that the waste does not begin to decompose and release toxic ammonia. In addition, the mechanical filter will not have any effect on impurities dissolved in water, including the waste products of fish. For these reasons, mechanical filtration is usually used in combination with biological filtration.
It is necessary to rinse the sponge of the mechanical filter with water at room temperature so as not to destroy the colony of beneficial bacteria that has settled in it.
It is used to optimize the nitrogen cycle by creating a suitable habitat for nitrifying bacteria. This habitat is a filtering environment.
At the same time, bacteria have a constant flow of food (that is, waste) and oxygen due to the flow of aquarium water through the filter. In any filter (mechanical or chemical), if you leave it in an aquarium so that water constantly flows through it, the necessary population of bacteria is formed, and then it will partially turn into a biological filter.
Biological filters should be disturbed as little as possible. Water should flow through them all the time – if you turn it off for more than an hour, the bacteria involved in the nitrogen cycle will die due to lack of oxygen and again it will take time for the biological “maturation” of the filter. Remember that it will take several weeks, and during this time your fish will most likely die due to ammonia and nitrite poisoning.
From time to time, a biological filter needs care – for example, wash the mechanical cleaning sponge. However, this should be done extremely carefully. Some filter care procedures result in the death of the bacteria that inhabit the filter, as mentioned above.
Therefore, when cleaning the filter in a biological filtration aquarium, special care should be taken.
Too acidic water may limit the effectiveness of biological filtration. Sometimes you can find statements that if the pH is less than 6.5, then it is below the optimal level for the activity of the bacteria inhabiting the filter.
However, in practice it turns out that biological filtration works even at much lower pH values.
For such filtration, fillers are used that change the composition of water by chemical means. Chemical filtration is used to improve the quality of water or to change its chemical composition. The following materials are used for chemical filtration:
– coal (activated carbon, activated charcoal) – to remove dyes (for example, methylene blue), some drugs, tannins (for example, peat), as well as some pollutants;
– corals (crushed corals or coral sand) – to increase or buffer pH;
– limestone (dolomitic) chips — to increase or buffer pH;
– peat – to lower the pH;
– zeolite (natural ion exchange resin) – to remove ammonia. Please note that the use of zeolite can only be a short-term measure and it should be done only in urgent cases (for example, to compensate for a temporary increase in the ammonia content). It cannot serve as a replacement for the nitrogen cycle.
After a short time, the zeolite loses its effectiveness, with the result that fish can be exposed to lethal ammonia concentrations. Coal also has a limited duration and needs to be replaced regularly.
Since it is preferable to remove contaminants from the water before you pour it into the aquarium, it is usually not necessary to use coal on an ongoing basis in the aquarium filter. He has a remarkable ability to remove some medicinal substances at the end of a course of treatment. For this reason, during treatment, coal, of course, should not be used.
Peat also need to be updated regularly. Corals and limestone are able to maintain efficiency for a very long time.