Why Filtration In An Aquarium?

2023 Author: Molly Page | [email protected]. Last modified: 2023-11-27 22:49

Sometimes we forget that the fish in our aquarium are limited to a very small amount of water compared to their natural habitat. In nature, fish waste immediately dissolves in the water, and in the aquarium, they quickly accumulate, which leads to water intoxication.

Waste includes ammonia from the gills of fish, their waste products, as well as leftovers from eaten food, which deteriorate and, in turn, form ammonia. Even very small amounts of ammonia can kill your fish.

Cichlids. © Photo Irina Bakhareva

Obviously, the more waste, the more acute the problem of ammonia becomes. A small aquarium overcrowded with large fish that is also overfed will have much more ammonia than a large aquarium with one small fish that is rarely fed. But in both cases, filtration will be required to control the level of toxic ammonia.

Some aquarists try to control ammonia levels only by changing the water. This is useful, but not practical. Fortunately, there is an easier way. In fact, our world is home to many bacteria that feed on ammonia, converting it into much less toxic substances. In many aquariums, these processes occur even without the knowledge of their owners. But experienced aquarists know exactly how to take advantage of these beneficial bacteria and maximize their growth.

When you set up a new aquarium, there are no favorable bacteria colonies in it yet. For several weeks, such an aquarium is dangerous for fish. You should gradually build up a source of ammonia (starting with one or two small fish) to allow time for favorable bacteria to grow.

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Remember that bacteria convert ammonia into other substances (nitrite first, then nitrate) that are less toxic. Many fish tolerate fairly high levels of nitrates, but over time, nitrates accumulate and become poisonous as well. And since nitrates are a fertilizer, their high levels lead to accelerated growth of algae.

Water change

While there are many ways to remove excess nitrate, the most effective is to regularly replace some of the water. This is one of the most important rules for maintaining your aquarium.

How often and how much to change the water depends on the amount of waste in the aquarium and the sensitivity of your fish. In no case should ALL water be changed at once, because abrupt changes in water composition are very harmful to fish. The best way to determine the frequency and volume of water changes is to regularly test the water quality using special tools available from pet stores. If you have a new aquarium, at a minimum, you should check your ammonia and nitrite levels. In older aquariums, nitrate levels should also be monitored.

On average, you can replace no more than a third of the water in one day. Many aquarists change a quarter of the water every two weeks on average. But you hardly have an "average" aquarium, so you should focus not on these numbers, but on the test results.

Two-tailed Indian glass catfish (Kryptopterus bicirrhis)

Biological filtration

Biological filtration is a term for stimulating the growth of bacteria that neutralize ammonia. There are several types of bacteria that convert ammonia into less toxic substances - nitrites and nitrates. These bacteria are not harmful and are abundant in nature. They are so common that we don't need to specifically add them to the aquarium - nature does it for us.

In the presence of ammonia and oxygen, these bacteria will naturally proliferate. They can be found throughout the aquarium: on rocks, gravel and even decorative elements of the aquarium. These bacteria only require compliance with the following conditions:

1. A surface on which colonies can form.

2. Ammonia for food.

3. Oxygen-rich water.

It sounds so simple that it begs the question: why do we need a mechanical filter?

In fact, if you're limiting the amount of fish that biological filtration can handle, you don't need a mechanical filter. Unfortunately, you cannot keep large numbers of fish alive with natural biological filtration alone.

Related article The nitrogen cycle: the key to biological filtration in the aquarium

Over the past few decades, many new types of biological filters have been invented that can significantly increase bacterial colonies to provide biological filtration for your aquarium. In essence, all of these types of filters provide additional surface for bacterial colonization and increased oxygen in the water.

Mechanical filtration

Remember that ammonia is not only produced by the gills of fish, but also made from fish waste and decomposing food. If you can mechanically filter out feed and excess food before it starts to spoil, this is great for fish health.

In simple terms, mechanical filtration is the removal of large particles from the water in an aquarium. Mechanical filtration does not remove ammonia. Most common mechanical filters do not remove microscopic bacteria and algae from the water. They also don't remove anything caught in gravel or stuck in plants or decorations.

Discus

You will need a different method for removing solid waste from nooks and crannies in the aquarium. One of the easiest methods is to "vacuum" the gravel during regular water changes, which should be done without fail. Please note that saltwater aquariums that use live substrates are an exception. Some people use suction pumps to improve mechanical filtration.

The most popular mechanical filters include sponges, paper cartridges and fabric filters. The holes are the smallest in paper filters and the largest in fabric filters. The holes in the sponge filters are medium in size.

Filters with smaller openings catch more particles but clog faster. In general, filters with a large surface area will clog more slowly than with a small area. When clogged, the filter begins to trap less and less particles. At some point in time, it becomes so clogged that it stops filtering water.

So, a good mechanical filter is one that captures a large number of particles, making the water clear, without requiring replacement too often.

Chemical filtration

Chemical filtration is designed to remove waste dissolved in aquarium water. Dissolved waste is found in water at the molecular level and is divided into two types: polar and non-polar. The most common chemical filtration method uses activated carbon filtration of water, which is effective against non-polar waste but also polar waste. Another effective method is protein filtration, which removes polar waste such as dissolved organics.

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Granular activated carbon is made from coal in the presence of steam at a very high temperature. This process creates many tiny holes in the coal that trap non-polar waste at the molecular level through adsorption and ion exchange, and remove heavy metals and organic molecules that are the source of unwanted color and odor through a process known as molecular sieving.

The best activated carbon filter has a macroporous structure (large holes). Good macroporous activated carbon is light and sizzles when thrown into water. Activated carbon filters, designed to remove wastes from the air (odors), are usually made from coconut shells and have a microporous structure. Air filtration carbon is denser.

Some reef aquarium owners are interested in phosphate leaching. Coal should be purchased from a well-known and well-established manufacturer. In this case, the coal is acid washed out during the manufacturing process to minimize the ash content. Coal with a low ash level reduces the likelihood of unwanted pH changes. In this case, a lower level of phosphate leaching also occurs.

Piranha Natterera, or ordinary (Pygocentrus nattereri)

Phosphate in activated carbon filters is a result of the fact that carbon is of vegetable origin and all objects of vegetable origin contain high levels of phosphate. At the beginning of using such a filter, the level of phosphate leaching is quite high, but after some time it decreases. This problem can be significantly reduced by soaking the charcoal several weeks before use.

Some aquarists are concerned that activated charcoal filters are removing trace elements essential for plants and invertebrates. Micronutrient deficiencies are a big problem in live aquariums and mini reefs. The potential benefits of coal are far greater than its disadvantages. If there is a risk of micronutrient deficiencies in your aquarium, simply use micronutrient supplements.

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Activated carbon cannot be recovered outside the laboratory, but fortunately it is very cheap and readily available. Always wash the charcoal before use and remove any dust that accumulates on it during transport. Use a small amount of charcoal, but change it frequently.

A variety of special chemical methods have been developed in order to remove certain chemicals. One of them is made from zeolite clay and is known under the trade name "Ammo-Carb" '. This filter removes ammonia from the water and is good for short term use. It should be noted that when using zeolite, especially when starting a new aquarium, biological filtration is disturbed. Protein filters are primarily used in salt aquariums, especially reef aquariums. They have a remarkable ability to remove dissolved organic waste before they decompose. This filtration process takes advantage of the polar nature of organic molecules, which rise to the surface along with air bubbles. The resulting foam is filtered.

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