There are three basic types of water filtration available for your aquarium. They are mechanical filtration, chemical filtration, and biological filtration.
The mechanical filtration of water is done by passing the water through a screen or thin pieces plunge. Also a floss material is sometimes used, which removes pieces of debris from the water.
Chemical filtration of water is done by testing the water through small pieces of carbon, which is a natural mineral. The carbon removes molecules such as ammonia from the water.
Biological filtration, a water is done by certain types of bacteria that live on gravel, the surface of glass, ceramic ornaments, plastic plants, or best of all bio-wheels. These bacteria are often called beneficial bacteria. In contrast to the pathogenic or harmful bacteria that cause disease. Beneficial bacteria in biological filters digest waste that is dissolved in the water by combining the waist with oxygen. That is also dissolved in water. These bacteria were very much like the bacteria in your compost pile that turns your organic waste into soil. Ammonia is very toxic to fish, nitrate is also toxic, but less so than ammonia. So the beneficial bacteria take oxygen and toxic ammonia from the water and produce rather harmless nitrates and more water. So biological filters are for the most part, devices that provide living space for the beneficial bacteria.
Types of Filters
The most basic type of filter is a sponge filter, consists simply of a sponge through which water is drawn by rising air bubbles. This bunch asked mechanically, and once matured biologically. These filters are ideal for small breeding in rearing tanks were a power filter might Sauk fry into the filter in one. They are also relatively inexpensive as all you need is the filter box, sponge and air pump.
Box filters are also air powered and come in the number of sizes to suit small to medium-size tanks. The airflow draws water through the chamber of the filter, which can be filled with the desired media. These filters are nice when an extra system is needed to take care of specialized problems such as too much ammonia or other nitrates in the tank.
Internal power filters utilized electronically powered centrifugal pump to draw water through the filter material. They may also have additional chambers for adsorptive media or additional mechanical or biological media. They generally circulate better than air powered filters. They are ideal for accordions that are to 2 to 4 foot in size. They can also be used in combination with external canister filters for larger aquariums.
Filters that hang on the back of the tank are popular in the US and other regions, they are similar to an internal power filters in the design principle, and the size of the aquarium they are suited for. Most now come with a disposable filter, that is filled with charcoal for double filtration.
Canister filters work on the same principle as internal power filters, but are positioned outside the tank and draw of water into the filter through an inlet to and return the water via another tube. Most are fitted with a spray bar to increase aeration of the tank. They avoid the need for an on-site a filter inside the tank, but had the disadvantage that they require priming before use, although modern designs now incorporate self priming devices. Very good choice for larger tanks, especially those with plants in them.
Under gravel filters work by drawing water from the tank down through the gravel substrate, which acts as a mechanical and biological filtration media. This approach is a huge surface area for filtration. The gravel does need to be vacuumed occasionally, however, to prevent the buildup of excess dirt in the gravel and beneath the filter plates.
