All EXT-3P (3-phase motors) can be used with an optional variable frequency drive. A variable frequency drive (VFD) is a controller that varies the voltage and frequency (hertz) of the pumps motor allowing you the ability to control the pumps water flow rate. The VFD can be used to schedule the pump to slow down during certain hours of the day to conserve electricity and speed up during other hours, such as after work or on the weekends when a larger flow over the waterfalls is desired. It can also be configured to slowly ramp up pump speed helping to reduce stress on the plumbing fittings during when the pump is starting up.
Aquascape has made it easy to simplify the plumbing with the EXT Pump Plumbing Kit (#48027) sold separately.