How should I backwash a DE filter to avoid damaging the grids?

Turn off the pump and wait 10 seconds for pressure to drop before moving the valve to BACKWASH. Restart the pump slowly to let pressure build gradually, backwash until the sight glass runs clear (2-3 minutes), then rinse for 30 seconds. Avoid sudden pressure changes, never backwash with the pump running, and don’t overshoot the backwash time.