Engineered to create superior water quality, the Fluval C4 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 slides out easily for quick cleaning. Activated carbon, located in an easily-manageable and removable basket, performs thorough chemical filtration and effectively removes toxins.In the final two stages, a Bio-Screen pad provides massive biological surface area for friendly bacteria to colonize, plus it blocks debris from entering a trickle chamber filled with C-Nodes that are super-charged for fast and efficient nitrification.The result is clean, clear and healthy water for aquarium life to thrive in.The Power Filter also features a patented refiltration control system that lets you slow down the water output, creating a gentle flow to protect delicate fish and plants. At the same, a slower water circulation increases water dwell time in the filter, resulting in cleaner aquarium water.The Power Filter's completely modular design allows you to manage each stage separately and make changes at different times to maintain continuous biological activity. This results in a stress-free environment and ensures clear aquarium water.Key Features :Extensive 5-stage filter produces clean, clear and healthy water for aquarium life to thriveProvide maximum surface area and optimum dwell times in all stages of the filtration processTwo mechanical, one chemical and two biological filter chambers2-stage mechanical filtration effectively traps large and fine debrisFoam slides out easily for quick cleaningActivated carbon performs thorough chemical filtration and effectively removes toxinsBio-Screen pad provides massive biological surface area for friendly bacteria to colonizeTrickle chamber filled with C-Nodes are super-charged for fast and efficient nitrificationAlso features a patented refiltration control system that lets you slow down the water output, creating a gentle flow to protect delicate fish and plantsSlower water circulation increases water dwell time in the filter, resulting in cleaner aquarium waterCompletely modular design allows you to manage each stage separately and make changes at different times to maintain continuous biological activity. Comes complete with a Poly/Foam, Activated Carbon, C-Nodes and Bio-Screen PadIdeal for use in 150 to 265 L (40 to 70 US gal) fresh or marine aquariums