5 Things to Know About Backwashing a Sand Filter

Backwash based on pressure, not a schedule A fixed weekly or monthly schedule is often wrong. Note the clean filter pressure after fresh sand or a deep clean, then backwash when the gauge climbs 8-10 PSI above that baseline.

Over-backwashing wastes water and hurts filtration Backwashing too often wastes water and can channel the sand bed, making filtration worse. Let the pressure gauge be your guide.

Under-backwashing causes poor flow and cloudy water Waiting too long leads to reduced flow and cloudy pool water. Check the gauge every few days during heavy use.

Backwash until the sight glass runs clear Run the backwash for a solid 2-3 minutes until the sight glass shows clear water, then rinse for 30 seconds.

Trust the pressure gauge, not guesswork The pressure gauge is the only honest judge of when to backwash. Your filter tells you exactly what it needs.