Aqueon Power Filters feature four stages of filtration-mechanical, chemical, biological and wet/dry-for the cleanest, clearest, healthiest water. Higher flow rates ensure higher dissolved oxygen content for healthier, more active fish. The internal pump design helps dampen noise, eliminates leaks and starts up automatically after cleaning or power interruptions. The Aqueon 30 filters 200 gph and it rated for tanks up to 30 gallons.