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How to Backwash a DE Filter

Detailed instructions for backwashing a DE filter.

Your DE filter should be backwashed once per month or whenever the pressure rises to 10 psi above clean pressure. Your clean pressure is the filter psi reading that you get right after you have cleaned the filter.If you have a variable speed pump, compare the pressure at about 2500 RPM, so you have an “apples to apples” comparison.

Backwashing a DE Filter

  1. Turn off the pump.
  2. Empty the skimmer baskets and trap basket before backwashing.
  3. Make sure that there is nothing blocking the path of the backwash water. In other words, make sure that the backwash line is not clogged with ice, or valved off.
  4. If you have a separation tank, make sure that the bag is clean and in place and that the valves are set in the proper position to allow the water to flow through the separation tank and back into the pool.
  5. Put the backwash valve in “backwash” mode.
  6. Turn the pump on, keeping a close eye on the pressure gauge on the filter. If the pressure jumps to 30 psi or above, turn the pump off and check for blockage.
  7. Watch the backwash water through the sight glass and when the water runs clear, turn the pump off and put the backwash valve back in “filter” mode.
  8. Repeat steps 4-6 three more times. Each time you do this backwash cycle, it removes a little more of the DE from the filter.You will not get all the DE and dirt out of the filter (which is why you do a DE filter clean every 6 months) but you want to get as much of it out as you can on every backwash.
  9. After running four backwash cycles (steps 4-6), with the backwash valve back in normal filter mode, add the proper amount of DE filter powder to the skimmer and let it suck through the pump and into the filter.
  10. The proper amount of DE is 1 lb of DE for every 10 square feet of filter area in your pool filter. If you have a 48 square foot filter, then you would use about 5 lbs of DE in your filter.


Use an orange DE scoop to make sure you get the right amount of DE in your filter. You can pick up this DE scoop at Pool Stop. One of the most common mistakes people make is not putting enough DE into their filter after backwashing.
If you want to enjoy your pool and just have fun then you can leave all this work to us. Let our Pool Stop Team take care of all your maintenance and repair needs. Call today and set up a weekly service agreement and a seasonal maintenance agreement to cover all your pool care needs.

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