Fluval C3 Power Filter (20 to 50 US gal)Engineered to create superior water quality, the Fluval C Power Filter provides extensive 5 stage filtration two mechanical, one chemical and two biological stages for outstanding results. The Power Filter is designed to provide maximum surface area and optimum dwell times in all stages of the filtration process. Rigorous 2 stage mechanical filtration is performed by a thick layer of poly foam that effectively traps large and fine debris. The foam