Under natural conditions, natural water is purified using natural filters if there is no negative impact of human activity. Naturally, the mechanisms of natural water purification also work in an artificial domestic water reservoir, but without external intervention it is very difficult and sometimes impossible to provide a clean habitat for aquarium animals without external intervention. Thus, biological filtration of water is necessary for each aquarium.
The need and meaning of biofiltration
In a number of types of cleaning – mechanical, chemical, biological – aquarium water biofiltration is, in the opinion of experts, the most important. What is the reason?
The fact is that in the aquarium there are always organic waste of fish and other animals, rotting organic matter. The decomposition of waste and gases exhaled by fish contribute to the release of ammonia, which, when dissolved in water, not only changes its properties, but also has a detrimental effect on the health of underwater inhabitants.
It is known from a school chemistry course that ammonia and some of its compounds (ammonium, for example) are toxic substances. As for aquarium fish, for them the lethal dose of ammonia is 0.2 mg / liter. For many fish, the maximum allowable dose is 0.02 mg / liter, but even with such a concentration, especially tender living creatures will not feel very comfortable.
Consequently, the concentration of ammonia and its compounds should ideally tend to zero. But how to achieve this? How to remove a toxic substance, if it is dissolved in a volume of water?
You can partially replace the water in the aquarium, and some aquarists believe this method is the best to reduce the concentration of toxins.
And here come to the aid of beneficial bacteria, processing toxic ammonia into nitrites, and then into nitrates, which are not toxic.
Thus, the biological method of water purification or biofiltration implies the mandatory participation of living microorganisms in the process of improving the quality of the aquatic environment.
Microorganisms themselves are present in the aquarium: on its walls, decorative elements, in water and soil. Of course, they neutralize part of the nitrogen compounds, but this part is very small. It is necessary to collect a large colony of these beneficial bacteria in one place and create a constant stream of aquarium water passing through this group.
The principle device of the aquarium biofilter has just been revealed in general terms.
Ceramic filler for biofilter.
Biofilter device and types of filter materials
First of all, it should be noted that there are no devices that perform only biological cleaning of the aquarium aquatic environment. Every aqua filter (external or internal) provides at least two types of cleaning: mechanical and biological. Some devices also have chemical filter media. Thus, the biofilter is a component of the device, a very important part of it.
Microorganisms that process ammonia should be able to settle on the substrate through which the aquarium water is pumped. There are several types of such substrate or fillers for biofilters, which are placed in special cassettes (compartments).
Foam filter. The most common materials are foam rubber and sintepon. They not only satisfactorily cope with mechanical purification of water from solid impurities, but also are well suited for the formation of a colony of bacteria. These materials are used most often in internal filters with a small workload.
Bioceramics filter. In external or, as they are also called, canister filters, ceramic rings or tubes (bioceramics) are often used as a filler for filter cassettes. They are not only an excellent substrate for the settlement of beneficial bacteria, but also a good spray of water carrying oxygen. And without oxygen, as is known, all living things die, including bacteria.
Plastic Element Filterat. In many modern filtering devices, one can see such a filler as small plastic balls with a ribbed cut surface. Water passing through such a filter is sprayed, supplying more oxygen to working microorganisms.
Glass filter. There is also a type of filter element, such as porous glass, which, thanks to a special manufacturing technology, is baked in a certain way. The result is a cellular structure, from which then small balls are made (with a diameter of 8 to 12 mm). Bacteria quickly colonize a similar substrate and successfully process toxic nitrates.
The modern industry produces a variety of biofilters with a variety of fillers of cubic, cylindrical, round shape, as well as combined options, such as, for example, plastic bio-balls with a sponge located inside.
Plastic balls for biofilter.
Overview of some popular models
Tetra EX Filter
The German company Tetra has long established itself as a manufacturer of reliable aquarium equipment, including filters. Devices of the middle class Tetra EX provide a decent level of cleaning in aquariums with a capacity of from 60 to 500 liters.
As a filler for biofiltration, both ceramic rings and bio-balls are used (depending on the model).
Devices of this brand belong to the lower supply systems, and the water is cleaned when it comes under pressure from the bottom up, passing through cassette-type fillers.
A feature of the technical device is that before turning on the filter in the network, it is necessary to create a manual thrust and fill the canister with water. To do this, in the upper part of the body there is a swap button.
JBL (Germany) specializes in the production of energy-saving filters. Biological cleaning in models of the JBL line is made in bioceramic fillers. Water enters the device from above, goes down along the side walls, passing the prefilter (mechanical cleaning), and then rises upward through the biosubstrate under pressure. Preparation of the system for operation is carried out in the same way as in the previous case.
Polish canister filters brand Aquael are very popular due to the low price and reliability. Filtration quality is average.
Instruments line Aquael able to clean the water in aquariums with a capacity of 100 to 700 liters.
Thus, the Unimax system, designed for large quantities of water, has two retractors and exhaust pipes. This results in improved mixing of the aqueous medium.
A colony of beneficial microorganisms located in a filler (bio-balls or ceramic rings) receives more dissolved oxygen.
It is impossible not to dwell on the Italian devices. Reliable and reliable systems from Ferplast have proven themselves in the work. Water enters the canister from top to bottom and, after mechanical cleaning under pressure, flows upward, passing through cartridges with filler (special sponges are used for bioceramics and varying degrees of porosity). Devices can work for years without leakage. The main thing is to maintain the filters in a timely manner without disrupting the technology of their disassembly and assembly.
The range of models of biofilters is very wide. But choosing a particular device, you must first take into account its performance.
Thus, in order to preserve the life and health of your pets, you should know the causes of the appearance in the tank of poisonous substances and ways to combat this phenomenon. This knowledge will certainly help when choosing the desired biofilter.
Video about creating a biofilter for an aquarium with your own hands: