DESC: The Whisper 20 Power Filter provides quiet and reliable filtration and promotes clear and healthy water. The Whisper 20 provides mechanical, chemical and biological filtration for 10 to 20 gallon, salt or freshwater aquariums. The Whisper provides mechanical Filtration with a dual-sided mesh that catches debris and fish waste in its dense fibrous network. Chemical Filtration is achieved with Ultra-activated carbon that absorbs odors and discoloration. Easy-to-use, Bio-Bag fiber quickly traps particulate matter, Ultra-Activated carbon removes dissolved contaminants, and Bio-Foam supplies plenty of surface area for optimal biological filtration. A specially designed reservoir prevents back siphoning in the event of a power failure. The Aerobic Frame is deeply etched to provide a receptive surface for critically necessary aerobic bacteria. Using the same Aerobic Frame and replacing only the carbon and mesh helps to maintain biological filtration. Aerobic biological filtration conver