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Aquarium Sponge Filters

Aquarium Sponge Filters

Updated on July 21, 2023
Reviewer Profile Photo
Reviewed by Don Spaeth
Petco’s National Aquatic Care, Education and Programs Manager
Sera L Shaped Sponge Filter

One of the oldest forms of aquarium filtration (and not just for small tanks), a sponge filter may be the right filtration choice for your aquarium! So, what is a sponge filter? As simply as the name states, sponge filters are essentially a porous foam or sponge that sits at the bottom of the aquarium. 

How Does a Sponge Filter Work?

Water is drawn through the sponge allowing for the growth of beneficial bacteria and trapping debris. It is this simplicity of design that many hobbyists are drawn to. The basic components to a sponge filtration system consists of a base and cap, lift tube and strainer. Most require airline tubing and an air pump to operate, although some can be attached to powerheads or external filters.  This is very similar to many canister and power filters that utilize foam for mechanical and biological purposes. Some aquarists also utilize a sponge filter on the intakes of their power filters to filter of large debris from the water before it enters the main filter. 

Sponge Pre-Filter

Using Sponge Filters to Lower Flow

Sponge filters are an extremely effective filter option for someone looking for lower flow within their aquarium. For the hobbyist that is growing their own fish foods like brine shrimp and blackworms, a sponge filter can prevent these small creatures from being drawn in and killed by a canister or hang on the back power filter. Additionally, they can be beneficial for aquarists caring for shrimp species like Caridina and Neocaridina.  This also holds true for those aquarists that are breeding and raising fry to prevent your new baby fish from being pulled into a power filter. Lastly, power filters may cause too much surface agitation for bubble nesting fish, like bettas or gouramis, making a sponge filter an ideal choice for aquariums housing these species.

This filter option is also great for smaller sized or different shaped aquariums where the addition of other mechanical filtration options is not possible. Even smaller sized power filters may cause too much water flow in a small aquarium causing a disruptive environment for the aquatic life. Sponge filters are also a great option for planted aquariums, allowing for as much biological filtration as possible without a strong water flow disrupting the natural aquascape.

Hospital or quarantine aquariums are another great candidate for sponge filter usage. Most treatment and quarantine systems are not setup on for continuous use and because of their infrequent use, a sponge filter system is quick to setup and get operational at very little cost compared to some other traditional types of filters. 

Sponge Filter

Sponge Filter Pros and Cons

Sponge filters are very easy to maintain; if a sponge becomes damaged, it’s as simple as replacing the sponge.  During water changes, they just need a couple good squeezes into the wastewater bucket to remove the accumulated debris.  One disadvantage to using a sponge filter though is the lack of chemical filtration. Sponge filters are rock solid performers when it comes to mechanical and biological filtration, but they do not have any way of filtering out dissolved organics. Although, some may argue that in a well maintained or fully planted aquarium the use of chemical filtration is negligible, making sponge filters one of the most widely debated forms of filtration for aquariums. 

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