The aquarium filter

After having talked about the importance of bacteria in the process of our fish tank cycling, it has come the moment to look at how the filter works. As a matter of fact, the filter is the place in which bacteria carry out their tasks in the best way. The proper function of an aquarium filter is to keep the water clean for our fishes’ health, supporting and favouring the multiplying of bacteria into the “filtering materials”, which the filter is made up of. It also allows in its inside the abidance of products that help the removing of some elements defined as pollutants of water.

We can say that a filter has three different filtration functions that are biological, mechanical and chemical.                                                                                                                                                               

The Mechanical Filter

The mechanical filter represents the first filtering level and it is the one of which we can mainly see the results into the fish tank. The sponge holds the greatest part of big detritus that circulate into the fish tank, such as fishes’ excrements, remains of feed or parts of plants, leaving the water of the tank clear. It is important to notice that even in sponges there are colonies of bacteria that are involved into the nitrogen cycle, but their action is limited. As a matter of fact, the sponge tends to rapidly obstruct itself and so bacteria, just as rapidly, stop to convert the pollutants.

Even though we suggest cleaning the sponges of the filter with the water used during the water change, this traumatic procedure damages the colonies of bacteria. This leads to a filter made only of sponges, great for tanks with a reduced population of animals or for a temporary tank, such as a quarantine tank, but less suitable for a management of aquaria with numerous populations and few plants.

In order to reduce the maintenance of the sponges of the mechanical filter, we suggest placing them in series according to their different porosity. In this way, water firstly goes through the ones with a bigger porosity and successively through those with a finer one (like Amtra Biocell Blue Foam). As we have said before, the less we touch the sponges the less problems the filtering colonies have. Therefore, it can become fundamental to insert, before the sponges, a layer of a much compact synthetic material, the so-called “perlon wool”, that can be frequently removed and substituted without ever touching the core of the filter itself.

The Biological Filter

The biological filter is the most important one for the fish tank. Even though we do not clearly see the effects we have learned how to be aware of the fundamental action for our fishes’ health. In order to work, bacteria need a support to which they attach and then multiply. The more porous the support is, the better bacteria are able to set themselves up, increasing the performance of the filter. For this reason, the shape of supports is fundamental in order to offer a greater surface as possible, granting, at the same time, the circulation of water. The most known and functional shape in the tank filter is the so-called razor shell one, such as Amtra Glax Ring, but it is also interesting the shape of Amtra Glax Stone Ultra, much more compact than the razor shell one, useful to the settlement of denitrifying bacteria in it. These supports are made of sintered glass or, in any case, inert materials that are pretty robust, very porous and unalterable in time.
The materials of the biological filter must be put after the mechanical filter, in order to avoid the obstruction their porosity because of the sediments, drastically decreasing the available space in the filter to bacteria.

The Chemical Filter

The chemical filtering system in the aquarium is not always fundamental, but it is necessary to remove some pollutants such as nitrates and phosphates when their levels are too high to be managed through the water change and the adding of bacteria. Even though we have to remove tannins and some other natural colourings of water released by the new root that we have bought for our planted tank, we will also have to insert absorbent materials into the filter.

The most famous materials for chemical filters are activated carbon such as Amtra Axorb or Amtra Xupra 2, which eliminate colourings and chemical remains (for example after a treatment) and resins in order to absorb nitrates and phosphates such as Amtra Phosphat-Reduct, Amtra Nitrat-Reduct and Amtra Cleanwater. There exist specific materials according to the substances that we would like to remove from water.

Which filter to choose?

For what concerns a small tank with many plants, a compact filter can be fine, even only a mechanical one, such as Amtra Filpo or Amtra Filpo Mini. A professional product is certainly Amtra Filpo Click, unique in its genre, thanks to its mechanical and chemical cartridge that are easy to remove, in a ‘click’, without having to extract the water filter. Another pro of this filter is the fact of being one of the fewest filter pumps on the market with a large section filled with suitable materials for biological filtration.

If you have an open-top tank, it is optimal even a hang-on filter, such as Amtra Niagara or Amtra Filpro Ex 500. Despite a greater bulk outside the tank, these filters have a better aesthetic, because they leave inside only the inlet filter. In this way, these filters are perfect if you want to set up a beautiful, small planted aquarium.

Regarding bigger tanks, it is necessary a better performing filter, maybe an inner one, in order to have an easier maintenance, such as Amtra Filtering Box Black and 50 or Amtra Filtering Box Black 150, with materials arranged one after the other, easy to remove and clean.

For those who search for better efficiency and aesthetic, we suggest an external filter. This solution makes the design of the tank clearer, letting visible just the inlet and outlet filter, which can be easily hidden by plants and decorations, and a greater volume of filtering materials to obtain a better stability of the system.

Now there is nothing left to do but to find the right filter for your aquarium!