Replacement Sponges for Hydro Sponge 4 PRO Aquarium Filter

The Hydro pro sponge filter allows more flow, oxygenation, and filtering than the finer sponges. In addition, they do not clog so easily and are therefore, easier to maintain. The coarse Pro series maintain their shape better when challenged with debri or current. Simple, economical, and efficient. When the power goes out, a sponge filter can keep on truckin' with the use of a battery operated air pump. Unlike a HOB, sump, or canister filter. There are air pumps available that automatically switch over to battery while the power is out, purchase one of those to go with your Hydro Sponge Pro filter for worry free operation. I have two Pro Sponge filters in my 40 gallon breeder tank, and do not mind the looks of it all.