Choose a pump that was built to go below the waterline, the AAPW400 Active Aqua Submersible Pump. Active Aqua's entire collection of pumps complete any grow setup, but for hydroponic systems, you can't beat the submersible line. All of Active Aqua's submersible pumps include multiple hose fittings so you get an exact fit every time. Each pump's powerful mag drive construction includes removable foam filters, impellers, rubber mounting feet to reduce vibration, and a 6 foot heavy duty power cord. Adjust the pump's flow to get things moving at your preferred rate. The Active Aqua Submersible Pump moves 400 gallons per hour and is recommended for 40 gallon reservoirs, but you can adjust the pump's flow to move at your preferred rate! The pump can be used for indoor/outdoor use, is environmentally safe & oil free, and is UL listed!