Sponge Filters

These filters are excellent biological filters and reasonable mechanical filters. They are simple and inexpensive. The type of sponge material makes a large difference in the filters bio capacity. One of the sponge filters benefits is their ease in cleaning, which in turn lowers the amount of organic material being broken down in the nitrogen cycle.


It takes only minute to clean a sponge filter by rinsing it used aquarium water, while it may take half an hour to clean a canister filter. It is recommended that the sponge filter be rinsed in aquarium water during a partial water change every week.

Canister Filters

Canisters are my choice for tanks forty gallons or larger, especially for show tanks, as they can be completely concealed and not detract from the appearance of the aquarium. Because canister filters force the water through the filter media, they are particularly good at removing particulate matter. Canister filters are adaptable to a variety of conditions.

Canister filtersare pressurized to force water through the filter media, rather than allowing it to flow past it as other filters do. This makes them ideal for heavy loads. By changing the type and volume of various media, it is possible to create a custom filtration system for the needs of your aquarium.

Water can be polished using diatomic sleeves, extra rings or sponges can be added to encourage bacterial colonization for increased biological filtration, or additional mechanical media can be used for aquariums that have a lot of particulate waste. Chemical filtration can be modified by using special resins to remove dangerous toxins.

On the negative side, canister filters are difficult to take apart for cleaning and maintenance, and they are difficult to get primed and restarted afterward. Canister filters are very good for saltwater aquariums or those with many living plants.

Hang-on Back Filters

Also called power filters, hang-on-back filters are the most commonly used type of aquarium filter, largely because they offer excellent mechanical, chemical, and biological filtration simultaneously. The standard power filter hangs off the back of the aquarium and sucks water up through a siphon tube. They are simple to install and easy to maintain.

Mechanical filtration is achieved by water flowing through a filter pad or floss. Chemical filtration is provided by the water flowing through an activated carbon filter, and biological filtration is offered by beneficial bacteria that form inside the filter cartridge. Power filters may be combined with a biowheel to provide increased biological filtration

Trickle Filters

Also called wet/dry filters, trickle filters are designed to expose the water to as much air as possible. This is accomplished by allowing the aquarium water to trickle over a container of media, such as plastic balls, strands, or floss. This exposure to air and water fosters large colonies of beneficial bacteria that break down wastes. These are especially popular for saltwater tanks, but are becoming increasingly popular in freshwater aquariums, as well. Chemical filtration is provided by placing chemical media in the filter.The biggest drawback is the fact that they clog fairly easily. The use of a mechanical pre-filter eliminates or reduces that problem.