The AquaClear 30 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 aquarium water. Its unique waterfall design enables filtered water to return to the tank silently, gently breaking the surface tension and creating beneficial oxygenation.