Valve between pump and filter.

[CarlD]

I dunno. But you MAY be able to lower the speed of the motor with a transformer. I don't know how well or safely that would work, but that would be like a 2 speed pump. Still, it could burn it out as well. Have to find an expert on electrical motors.

[swimdaddy]

I have often wondered if you could use a simple rheostat to control the speed of the motor, like any other electric motor used in electronics. Heck, even my electric chain saw runs faster or slower depending on how far I pull the trigger.