Sponge or Breeder Filters

Filtering Your Aquarium Water

What Is It?

Sponge filters are any filters where the water is drawn through a sponge mounted or sitting inside the tank. Most of the time, these filters have a replaceable sponge and are powered by an external air pump. The sponge itself mounts to a core which, in turn, mounts to a lift tube and air line or a water pump. The sponge may rest on the bottom of the tank, in which case you can put it on, in, or under the gravel. Other models will mount to the side of the tank and should be placed as close to the bottom as they will fit to provide optimal water circulation.

How Does It Work?

A sponge filter uses bubbles of air from an external air pump, or an integral water pump to draw water through the sponge. As water is drawn out through the lift tube or pump, it is replaced by water entering the sponge. The sponge is a mechanical filter and the surface of all the bubbles or pockets in the sponge provide a bed for the bacteria of a biological filter. Sponge filters provide both mechanical and biological filtration.

What Maintenance Does It Require?

The sponge will need to be rinsed or replaced every time it becomes dirty, about once every 1 to 4 weeks, depending on tank load, kind of fish, feeding schedule, type of food, cleaning schedule, and what other filtration is available. Some sponge filters have small carbon cartridges which need to be replaced regularly or can be left off entirely. Remember that carbon cartridges that become saturated with waste chemicals could potentially release other toxins into your tank.

What Should I Be Aware Of?

Most sponge filters are reasonably efficient filters for small volume tanks. These filters, especially the air driven ones, are excellent for hatcheries, maternity tanks, and fry tanks, as the filter produces minimal current and has almost no way to suck the fry through the filter. However, the regular maintenance of the filter requires the replacement of the filter media. If you have a sponge filter in a display tank, you should consider getting a second filter so that you do not remove all of your bacteria bed every time you replace the filter sponge. Removal of the biological filter media (and its bacteria bed) will cause your tank to cycle again, which can be fatal to your fish. Remember to remove any carbon from the tank or filter before you medicate (if the carbon is working, it should remove the medication from the tank in under an hour, in which case your fish won't get treated).

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Page most recently modified: February 19 2007 17:42:32.