Usually used with a return pump, this flow sensor can be placed in line with the flow on any pipe, connected to the FMM, and communicate to your Apex the flow rate of water through that pipe. The FS-50 will work with flow rates from 30-250 gph, and will connect to any standard 1/2" Slip PVC. The flow sensor itself uses British Standard Parallel Pipe (BSPP) threads so two specially designed PVC unions are provided with slip fittings to adapt it to standard 1/2″ PVC plumbing.