The sand provides excellent water filtration as the 6-function control valve allows the pool owner to: filter, backwash and rinse, recirculate, drain and close the system.With the six-function control valve, you can choose between six different operating modes, including filtration, backwash, rinsing, recirculation, draining, and system shut-off.The built-in 24-hour timer allows you to set your preferred operating time for the filter pump.Through the pressure gauge, you can constantly monitor the water pressure.