The WS1 Twin Alternating control valve maximizes softener capacity and optimizes salt efficiency. This 1-in. valve provides a service flow rate up to 30 gpm and a backwash flow rate up to 16 gpm, with the meter and bypass installed. It has backwash and brining capabilities up to a 21-in.-diameter mineral tank. It incorporates patented seal-spacer stack assembly and patented technologies from the WS1 and WS3 valves.