It is mportant to set up the plumbing properly with the EXT pumps. Improper plumbing setups can lead to failure or damage to the pump. We recommend an Aquascape EXT Pump Plumbing Kit. The EXT Pump Plumbing Kit provides all the necessary fittings and valves to make the EXT pump easy to install, prime, and operate. Once primed, the pump can be turned on and off without priming if water remains in the suction line.