ProSense water softening systems combine the high efficiency advantages of a twin alternating unit with water quality sensors. As the resin bed exhausts, two sensors monitor its exhaustion rate. At the same time the turbine meter in the control valve is feeding water volume data into the controller. The controller compares the exhaustion rate against the water volume used and, at each regeneration cycle, recalculates the water hardness value in the programming. Combining a meter with resin exhaustion sensor technology, ProSense series water softeners solve the efficiency issues created by changing water hardness.