Aquarium Filters and Pumps

Filters  and pumps  are an essential component of your aquarium for two reasons: First, they aerate the water, and second, they remove harmful debris from the water. Though fish don't breathe air, they need oxygen to survive and are sensitive to nitrogen. Increased levels of nitrogen created by garbage, excrement, or a dead fish in a tank could be fatal to an otherwise healthy fish.

To figure out what kinds of filters you need, first pick your fish, then your tank,

The Three Types of Filters

The main types of filter systems  available on the market are biological,  mechanical,  and chemical.  Many of the newest types of filtration systems use one or more of the following methods for filtration to improve effectiveness and user convenience. They come in both internal  and external  styles.

Biological

This type of filter consists of living organisms that feed off the ammonia produced by waste in your tank. The nitrifying bacteria then produce nitrates that are used by the fish and the plants to grow. Such biological filters will live in the gravel and other safe areas of an aquarium. Because they are living they can die off and need to be replaced. They take awhile to develop so other methods of filtration should be used until they can fully develop.

Mechanical

Through the use of gravel, foam, or diatomaceous earth, mechanical filters  trap particles in the water. They act somewhat like a continual vacuum. Often these come in external filter form. They may also contain some carbon to enhance their filtration ability. They can clog, so they need periodic cleaning. Under gravel filters  also use mechanical filtration in the form of an air pump and they can be very effective if installed properly. They are an all-around good choice for all aquarium types. They are inexpensive, provide aeration and clean up the gravel. Sand filters  are external power filters that use foam, carbon, or floss. They must be changed periodically.

Chemical
	The most common type of chemical filtration system is activated carbon  (pictured, left). Less common methods use ammonia-absorbing clay and ion-exchange resins.

Multi-Filtration Systems

• Canister Filter : Very efficient, good for large aquariums with many fish. Uses all three filtration methods.
• External Power Filter : Powered by a water pump. Uses all three methods of filtration. Needs periodic cleaning and emptying. Can be combined with an under gravel filter for optimum filtration.
• Internal Power Filter : Uses electricity to run a mechanical and chemical filter. Space-saving.
• Corner/Box Filter : Uses all three filtration methods and it is powered by an air pump.

External Links

• Age of Aquariums -- A forum on equipment and chemicals.
• Aquatic Hobbyist -- A filtration glossary and pros and cons of the different methods.
• Fishfriend -- The pros and cons of specialized filtration systems.