Biological Filtration

This is the most important type of aquarium filtration system. It consists of good bacteria that deal with biological waste (in the form of ammonia) in the water. By metabolizing ammonia, biological filters help keep ecological balance in the water. Sponge filter is one of the most commonly used biological filtration tool. A sponge filter takes water from the take, pass it through a sponge where good bacteria live, then release the water back into the tank. Some biological filters also feature other types of filtration. Examples of biological filters are are canister filter, live rock/live sand, under gravel filter, bio wheel, and trickle filter.

Mechanical Filtration

This removes free-floating particles or solid waste (e.g. dead plant matter) in the water before they decay. There are many types of mechanical filter on the market; they can clean your aquarium to a varying degree of fineness. Cartridge filter, sand filter, bag filter, screen filter, disk filter, and swilter filter are the most popular. Mechanical filters need to be cleaned and replaced on a regular basis to prevent waste products from accumulating and decomposing.

Chemical Filtration

Chemical filtration is the process of removing chemical impurities and dissolved wastes in the water. This is done through use of activated or chemically treated media such as carbon, carbon zeolite, and peat moss. There are also a variety of methods available for chemically treating aquarium water. Popular methods include: adsorption, ion exchange, and chemical bonding. Some of the most commonly used chemical filters are: trickle filter, power filter, foam filter, and foam fractionization .