Aqueon QuietFlow 75 LED PRO Power Filter feature five stages of filtration-mechanical, chemical, biological and a specialty filter pad - for the cleanest, clearest, healthiest water. Easy-to-replace filter cartridge contains 25% more activated carbon than the leading brands to effectively remove dissolved organic waste materials. Our patented design includes unique features to enhance water quality and clarity, increase oxygen levels and lessen noise. The internal pump design helps dampen noise, eliminates leaks and starts up automatically after cleaning or power interruptions. This unit is preloaded with 2 large Aqueon replaceable filter cartridges.