Filtration And Various Methods Of Purification And Disinfection Of Water In The Aquarium

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

In the aquarium, there is a constant accumulation of organic residues (not eaten food, fish and shellfish excrement, dead inhabitants). Under the influence of oxygen and microorganisms, these residues decompose to simple mineral compounds (CO ₂, NH ₃, PO4.3-, S04.2-, NO ₃ - and others).

In natural reservoirs, the concentration of mineral substances in the water is quite stable, since some of them are assimilated by plants, and the other part is carried out along with the water flow. In an aquarium, the stocking density of fish is much higher than natural. Therefore, all organic material in the aquarium volume cannot be converted to inorganic substances.

With a lack and in the absence of plants, there is a gradual accumulation of minerals in the water. When a certain concentration is reached, the toxic effect of metabolic products on the inhabitants of the aquarium begins. Organic residues that do not have time to decompose form sludge, which makes the water cloudy, closes the soil, preventing oxygen exchange.

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To remove excess mineral and organic residues from the aquarium, cleaning and water changes are carried out, as mentioned above, and the aquarium water is filtered. The main purpose of filtration is to remove unwanted constituents (organic and mineral particles, molecules, ions, microorganisms) from the water. Aquarium filters generally come in two types: mechanical and biological. In addition to filtration, there are several more methods of water purification: chemical, flotation, ozonation and ultraviolet irradiation.

Red parrot or parrot fish

Mechanical filtration

Mechanical cleaning consists in removing suspended particles and algae from water by passing water through a filter element. Particle removal occurs when water seeps through narrow channels of filter material (gravel, mesh, fibers, etc.). The cleaning efficiency increases with a decrease in the particle size of the filter material or the diameter of the passage channels. However, the reduction of the channels is possible only up to certain limits, since in this case the resistance to the liquid flow begins to increase and the performance of the filter decreases. During filtration, suspended particles begin to settle at the very beginning of the filter, reducing the diameter of the passage channels. This leads to a more complete water purification in this area, while the subsequent layers of the filter element work less efficiently. Therefore, a filter layer thickness of more than 5 cm is not required. It is advisable to use filter elements with different sizes of passage channels. Water, successively passing through layers with ever-decreasing channels, will be uniformly cleaned throughout the entire volume of the filter.

Depending on the speed of water passing, filters are divided into fast and slow. The source of water movement in slow filters is usually airlift. The principle of its operation is as follows: the air flow from the compressor in the form of small bubbles is mixed with water; the gas-air mixture rises in a narrow vertical channel (cut) above the water level in the aquarium. Thus, water is pumped through the pipe, and the filter element can be installed at the entrance to the pipe or at the exit from it.

In fast filters, the source of water movement is mechanical (most often centrifugal) water pumps (pumps}) They create a high pressure of water, thereby ensuring a higher circulation rate through the filter element.

Bacteria settle on the surface of the filter element, converting organic compounds to mineral ones. However, since the volume of mechanical filters is small, they do not completely decompose organic matter. There is one mistake aquarists make when using mechanical filters. During operation of the filter, microorganisms living in it oxidize organic compounds, for this they need a constant supply of oxygen. Some aquarists at night, avoiding noise or following the instructions for use of the compressor, turn it off, cutting off the oxygen supply to the filter. In the absence of oxygen, instead of almost harmless substances, hydrogen sulfide H ₂ S, methane CH ₄, ammonia NH ₃, which are highly toxic for fish, begin to be produced… During the shutdown of the filter, these substances accumulate in it and, when turned on again, are immediately thrown into the water in large quantities. This can lead to massive poisoning of fish or injuries associated with a jump in water parameters (primarily pH). Therefore, aquarists should not shut off running mechanical filters without flushing or replacing the filter element.

Related article Protecting your aquarium from toxins

During operation of the filter, the accumulation of filtered material occurs in it. It is necessary to periodically flush the filter element. It is not possible to give an exact recommendation on the frequency of flushing, as it depends on the volume of the aquarium, the number of fish, the number and rate of plant growth, the volume and design of the filter. However, in all cases, after 1-2 weeks of continuous operation, flushing is necessary. These terms can only be clarified in practice.

Now let's dwell on the structural elements and technological features of the filters. Depending on the installation location, a distinction is made between external and internal filters.

The basic design of the internal mechanical filter is shown in Fig. 26 … The filter consists of a housing (1), in which there are two openings: one large inlet (2) and another outlet (3) of a smaller size. In the outlet channel, you can lower the atomizer connected to the compressor, thereby creating the simplest airlift. In this case, the diameter of the inlet should be slightly larger than the diameter of the atomizer. If a filter is to be connected to a pump, then the design of the outlet must match the diameter of the connecting hose and provide a reliable and tight connection to the pump. The inner cavity of the filter between the restriction grids (4) is filled with a filter element (5), the filter element must completely fill this cavity, otherwise unfilled channels may form through which the main stream of water rushes.