Some DE filters have the ability to run a back wash or clean cycle, without opening the tank.Consult with your filter’s owner’s manual for the steps required.
To do a full clean, power off the pool pump.
Open the filter tank, and remove the DE filter media.
Rinse the filter media until it is free of old DE, and debris.
Re-insert filter media in tank, and close lid.
Turn the pool pump back on.
Add DE according to manufacturer specified dosages.