Backwashing a Sand Filter
Sand filters clean pools gradually, removing dirt, debris, and particulates as water passes through a deep bed of sharp sand. With the proper kind of maintenance, these filters will last many years.
Backwashing is a simple matter of reversing the flow through the filter by sending water up through the underdrain or laterals and diverting the outlet water to waste. Backwashing cleanses the sand of dirt and oil particles. Without proper backwashing the filter will short cycle, channel, and deliver poor filtration. However, backwashing too often too often will allow smaller particles of dirt to pass through unfiltered.
How do you know when to backwash?
Clue #1: Your water is cloudy
Clue #2: Your filter’s pressure gauge alerts you. You should backwash with the pressure increases by 8-10 psi from initial post-backwash readings.
Clue #3: If you have low flow through your skimmers or return inlets, it’s time to backwash.
- Turn off the pump
- Turn the control valve to BACKWASH and turn on the pump.
- Allow the system to backwash for 2-3 minutes, or until the water gauge looks clear.
- Turn off the pump and set the control valve to RINSE.
- Turn on the pump for one minute, and then turn it off again.