Backwash your DE filter when the pressure gauge says so.

When the pressure gauge reads 8–10 psi above the clean baseline (the reading right after you backwash and recharge), it’s time. That’s the rule. Ignore the calendar.

Following a fixed schedule is a waste of time. Some weeks your pool gets heavy use and debris — you’ll need to backwash every few days. Other weeks it’s calm and you can go two weeks or more. The gauge never lies.

Signs besides the gauge: lower water flow from returns, weaker skimmer action, or cloudy water. But the gauge is your primary indicator. Clean your filter, note the pressure, then backwash when it climbs 8–10 psi. After backwashing, don’t forget to add fresh DE — the old stuff gets flushed out.

Trust the gauge. Your pool will stay cleaner with less effort.