As dirt accumulates in the swimming pool filter bed, resistance to flow increases, which causes a reduction in water discharge to the pool. When the flow is insufficient for proper water circulation, it is required to clean the pool filter. This process is referred to as backwashing.
The correct backwash rate for a high-rate sand filter is the same as it was when the pool filter was in the “filter cycle” (15-25 gpm per square foot of the filter area). In rapid-rate sand filters the backwash rate must be between 12-15 gpm per square foot of filter area (which is 4-5 times greater than the average filter rate per square foot).
To backwash a sand filter:
- Turn off the pump (Never change the filter control valves with the pump running).
- Turn the control valve to the “backwash” position.
- Turn the pump on and allow it to run until the effluent water is clear as seen in the sight glass at the backwash valve or waste piping. This takes about 2-4 minutes.
- Shut off the pump and turn the control valve to the “rinse” position.
- Turn the pump on for 20-30 seconds. This resets the sand bed and sends any residue of dirt into the waste line rather than into your pool.
- Shut off the pump again and return the valve back to the “filter” position. Turning the pump back on resumes the filter cycle.
Any further questions? Please refer to the manufacturers guide or manual.