When to Backwash a Sand Filter
- Increased PSI. PSI (pounds per square inch) is a unit of pressure measurement when the filter is running. It's time to backwash your sand filter when the pressure gauge is 8–10 psi higher than the normal baseline.
- Decreased water clarity. When you notice that the pool water is cloudy or you see floating debris that the filter seems unable to capture, it is likely that the sand filter is significantly less efficient or unable to filter.
How to Backwash a Sand Filter?
- Turn off the pool pump and turn the multiport valve to the backwash position, ensuring the handle is locked in place.
- Connect the backwash/waste hose and place it where you want to discharge the waste water.
- Turn on the pool pump and run the pump for at least two minutes. The water in the sight glass will change from cloudy to clear.
- Turn off the pool pump again. Turn the multiport valve to the backwash setting, ensuring the handle is locked in place. The backwash setting will reset the sand and flush the remaining dirty water into the waste.
- Turn on the pool pump and run the pump for 15–30 seconds.
- Turn off the pool pump again, turn the multiport valve back to the filter position, ensuring the handle is locked in place.
- Turn on the pool pump and let the filtration system run normally.
- Check the filter pressure gauge and confirm that the pressure has returned to the normal baseline.
