AquaClear 50 Power Filter - 20-50 Gallon Aquariums - Includes MediaThe AquaClear 50 Power Filter features a unique multi stage filtration system that provides complete mechanical chemical and biological filtration for superior water quality. The Power Filter has a filtration volume that is up to 7 times larger than comparable filters. It also allows superior contact time with filter media. The filter preserves beneficial bacterial creating a stress free environment for aquarium inhabitants and maintaining clear