Aquatop's Weighted Sponge Filters are simple to use; very easy to clean and highly effective. The foam material is designed to remove fish waste and debris and enhance the growth of beneficial biological bacterial; improving overall water quality in your aquarium. Great for all applications; including breeding or hospital tanks. Sponge filters can be powered by an air pump or power head. To clean just simply remove the sponge and rinse with non-chlorinated water. The CAF-180 model is rated for aquariums up to 180 gallons. For more information on sponge filters; please read our article on Sponge Aquarium Filter Basics.