raditional AC pumps when used as a return pump for your sump are flow controlled through the use of a choke valve. This is method of control is inherently inefficient for two reasons. 1) The AC pump purchased must often be over-powered for your given setup to allow for flexibility. 2) By adding artificial impedance to your flow, electricity is wasted. The Vectra pump will always operate at the optimum efficiency because there is no need to use a flow restricting valve to achieve your desired flow rate.