Whisper Power Filters Are The Best-Selling Brand Of Power Filters In The U.S. Appropriate For Every Size Aquarium, They Provide The Three Types Of Filtration That Your Aquarium Needs: Mechanical Filtration -- To Remove Particles Such As Uneaten Food, Bits Of Plants, Fish Waste, Etc., From The Water Biological Filtration -- To Provide For The Growth Of A Colony Of Beneficial Bacteria That Will Eliminate Harmful Toxins In The Water Chemical Filtration -- Activated Carbon Removes Compounds That Cause Odors And Discoloration Of The Water

T25772 Whisper 20 Gallon Filter