Wavemakers destroy the brake system that engages on start to make sure the prop only spins in the correct direction.. The pump has to run for at least one hour after start to retract the brakes and sufficiently cool, lubricate and rinse before turning off. The water in the aquarium is what rinses, cools and lubricates the pump and so new water must replace all the water inside and flush out any debris. For this reason wavemakers void the warranty and innevitably will destroy the pump.