DE filter backwashing


Jun 27, 2009
I have a Pentair DE filter, 80 SQ ft.and Variable pump, Pentair VS 3050, 22000 gal pool, inground.
After backwashing the DE filter, how much DE media should I add back ?
It seems that the pressure on the filter gauge varies with the speed of the pump, so which speed would accurately reflect the true pressure of the filter ?



TFP Expert
In The Industry
Jun 12, 2009
Exeter, PA
There is A chart on the filter with how much to use Although I usually use half that amount and the filter still works fine. Use the full speed pressure as a guide


LifeTime Supporter
May 21, 2007
Cape Coral, FL
I have a similar Pentair DE filter-although 60ft3. Make sure you get a good backwash-using as a high a pump speed as possible will aid in flushing. I for one follow the practise of 'backflush' until the bullseye is clear-then shift to 'rinse' for 10-15sec, then back to 'backflush', and at least 4 of those cycles. I then reload DE after venting the filter to ensure full of water, and I load the recommended amount of DE (for me its 6lbs) via one of the skimmers with full pump flow. When I winterize, I always take apart the filter and pull the grids to ensure no DE in the bottom (never found any), and I also wash off the cloth grids.

Using this method, I have never found any excess DE material laying in the bottom of the filter can. Some people suggest loading less than spec on the DE amount to ensure no buildup of DE, but I have found with thorough back-flushing at a high pump flow, I do not get any buildup-this method may use some additional water.

My pump is a single speed 2hp pump for a 29000 gal pool. My DE press empty of DE is 22psi and 23psi full and I replace the DE every 30 days.

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