Sponge/Foam Inserts and Sleeves
These are replacement sponge/foam blocks and inserts for various filter types. To browse by your brand/model of filter, check our Shop by Brand section. We carry stand-alone sponge filters too.
Sponge provides both mechanical and biological filtration - it removes particulate matter and detritus from your water, and provides surface area for bacteria to populate and detoxify your water of ammonia, nitrites and nitrates. If you've got a sponge as your primary biological filter, make sure you have a separate mechanical prefilter (another sponge can work) so that your bacteria bed doesn't clog up quickly.