Aqueon QuietFlow LED Power Filters 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 waste materials. Our patented designs include 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. A great benefit of the Aqueon QuietFlow filters is the internal pump design that helps dampen noise, eliminates leaks and is self-priming, meaning it starts up automatically after cleaning or power interruptions.