Filtering an aquarium is not always as simple as A-B-C. Filters can break down, special circumstances may arise, or the aquarium in question may have very specific needs. Money can also be a significant consideration. Sponge filters are designed to be flexible and easy to use. They are ideal for beginners and have plenty of applications for advanced aquarists.
How Sponge Filters Work
Sponge filters have a very simple design. The sponge itself sits upon and surrounds a small plastic frame. Airline tubing runs from an air pump to the sponge. Inside the sponge base there is another very short piece of hose connected to an air stone. The air pump pushes air through the stone at the center of the sponge and the air rises out through the top of the filter, usually through a tube. This air movement creates a gentle suction effect, drawing water and debris through the sponge. Debris, loose material, and waste are drawn into and trapped in the sponge, waiting to be rinsed out.
Thus, all that is really needed for proper operation of a sponge filter is a sufficient air pump and an air stone. The sponge will act as a filter and provide aeration at the same time.
The sponge also acts as an effective medium for nitrifying bacteria to colonize. The presence of such bacteria in the aquarium provides substantial biological filtration: breaking down ammonia and nitrites into less toxic nitrates.
Uses for Sponge Filters
Sponge filters have several practical applications in the aquarium hobby. Any serious hobbyist or fish breeder should have several of these on hand to meet any problems or special situations that may arise.
- Aquarium Filters – Sponges are efficient aquarium filters, making for excellent nitrifying bacteria colonies and effective biological filtration.
- Pond Filters – Just as with aquariums, sponges and sponge media are commonly used to provide filtration for ponds of all sizes. Sponge filters can also provide extra aeration for ponds.
- Filters for Breeding Tanks – When fish fry are present in the aquarium, there is always the risk of them being sucked into the filter. With a sponge filter and its gentle water flow and lack of moving parts, this problem is eliminated. Further, sponge filters create very little water turbulence, especially when using a flow control valve. This is very useful for breeding fish that are bubble-nest builders: the flow of bubbles released can be turned down so as not to disturb the nest, but keep the aquarium adequately filtered.
- Cycling New Aquariums – Sponge filters that are used and established are great tools for cycling a new aquarium. Essentially, the aquarist adds the sponge filter to the new aquarium at the beginning of the cycling process, and the sponge “seeds” nitrifying bacteria into the water, thereby speeding up the process.
Maintaining Sponge Filters
Aquarium sponge filters are very simple to maintain. Whenever a water change is being performed, disconnect the sponge and rinse it thoroughly in the water that was removed during the water change. Do not rinse it with tap water.
If a sponge filter is rinsed in tap water or any chlorinated water, the chlorine will kill the nitrifying bacteria that has colonized the sponge, significantly reducing its effectiveness.
Sponge filters may show wear over time and need to be replaced. This is especially true with certain fish or invertebrates that will tear or bite at the filter. The sponge alone is very affordable and readily available at most local pet stores.
Anyone who is serious about keeping or breeding fish should have sponge filters at their disposal. They can aid an aquarist with sudden problems or unexpected situations, speed up the cycling of an aquarium, help for make-shift tanks, and are virtually indispensable when it comes to breeding fish. For practical and economic value, they can’t be beat!
Aaron Guzman - Aaron Guzman currently lives in Eureka, California and works as a freelance writer. He spends his spare time writing fiction, playing ...
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