Fishes Health Cards N°02. Filtration of your aquarium

Filtration of your Aquarium

Regardless of the type of aquarium you own, and regardless of the species and number of fish and plants that are housed there, water filtration is essential. In fact, very quickly a number of organic waste will accumulate, polluting the water and compromising the proper biological balance of your aquarium and the health of its residents. This waste is visible to the naked eye (plant debris, food remains, animal waste ...), but also invisible: it is the nitrogenous waste, which is responsible for the increase in ammonia and nitrate levels in water , And which are obviously harmful to the health of your fish.

The two fundamental principles of filtration.

There are two types of filtration: mechanical filtration, and biological filtration. In practice, these two types of filtration are generally carried out simultaneously and in the same place. We separate them here for a better understanding.

Mechanical filtration.

It is a matter of filtering and clearing the water from your tank of all debris visible to the naked eye. To do this, the water is passed under pressure through a filtering mass of different types possible, the waste then remaining imprisoned therein. This filtration can be done in the aquarium itself, or outdoors.

Biological filtration.

This filtration is carried out by the use of so-called nitrifying bacteria: they use nitrogenous waste for their metabolism, and thus clear your aquarium. As a rule, these bacteria naturally colonize the mechanical filter media, whether it is the sand or the substrate itself, or any other filter material used.

Different methods of filtering.

Filtration under sand.
It is a simple, economical method used conventionally for small aquariums (<60 liters). A plate of the same surface as the ground of the aquarium, pierced with small holes, is placed under the sand or the substrate. These plates are usually made of plastic. Its edges allow it to slightly raise it from the bottom of the tank in order to promote a good circulation of water. A vertical tube containing the pump is fixed to the plate to ensure the return of the filtered water to the upper part of the aquarium. It is the sand or the substrate itself, used as a sieve, that will act as a filter. The pump sucks the filtered water under the plate, creating a vacuum, attracting the water from above, which, aided by gravity, is filtered by the soil and is found under the plate, in order to be sucked By the pump.

The sand or substrate is quickly colonized by nitrifying bacteria, which will ensure biological filtration.

However, this method has the disadvantage of being partial and there are materials which will not be completely degraded: it will therefore be necessary, very regularly, to empty your aquarium and to clean thoroughly and deeply the sand or the substrate, in order to get rid of the waste Filtered.

Vertical filtration
This type of configuration is easy to maintain. The filters generally consist of a cylindrical tank. The sucked water passes through one or more filtering masses and is then discharged into the aquarium. A tube of the same height as the tank and drilled with holes is placed at the center of the filtering masses to increase the surfaces in contact with the water. This type of filtration is used for medium-sized aquariums. (<100 L)

The gutter filter, or dry filter or trickle filter
This is the most effective method. It is used for large aquariums. A pump sucks water out of the aquarium, either into the lighting gallery above, or into another tank located under the main aquarium. The water then passes through several filtering masses, then is discharged into the aquarium. The return of water to the aquarium is usually in the form of rain or waterfall, which causes a noise that stimulates the reproduction of several species of fish (simulation of the rainy season).

Filter materials

The perlon
It is a widely used material, white in color, easy to clean, but must be changed regularly.

The polyurethane filter
It is the most used material. Very resistant to prolonged immersion, it cleans very easily like a sponge with clear water. It is advisable to replace it every quarter.

The ceramic tubes
Their characteristic is to be very easily colonized by de-nitrifying bacteria thanks to their high porosity.

Activated charcoal
Due to its exceptional adsorptive qualities, it is used punctually and temporarily to combat the bad odors of water. It quickly loses its effectiveness.

For large filtration systems, it will be advantageous to use several filtering materials simultaneously. (Ceramic tubes + activated carbon for example, or ceramic tubes + polyurethane filter)

The filtration flow.

The filtration flow depends on the power of the pump, but also on the compactness of the filter material. The filtration flow will be selected and adjusted according to the population of fish present in the tank, the plants and the size of the aquarium. Some fish consume a lot of oxygen (Cichlids) or others have a great need of current: it will be necessary to choose a filtration rate of 3 or 4 times the volume of the tank per hour or even more for some very polluting species. Conversely, smaller fish, or quieter and more fragile fish, will not have to undergo a flux greater than 1 or 2 times the volume of the tank per hour. For aquariums rich in plants (which consume carbon dioxide and release oxygen by photosynthesis), a high flow rate (very oxygenating) is not recommended.

In all cases, do not forget to place a strainer at the mouth of the suction to avoid aspiring the smaller fish (fry). On the other hand, do not clean all the filter media simultaneously so as to allow the nitrifying bacteria time to colonize the cleaned material from the dirty material.