Swimming Pool Service and Cleaning - How to Clean your DE filter

DE Filter Maintenance

A DE filter offers the best possible filtration, but it also requires the highest level of maintenance. 

Backwash Instructions

DE filters should be backwashed when the pressure rises to 5-8 lbs above normal or every four weeks, whichever is sooner.  If the DE filter goes less than 3-4 weeks between backwashing on a home pool, then it may be time for a DE filter clean.  The DE clean should be done once or twice each year.

The backwash process is as follows:

  1. Empty the skimmers (so that you are not sucking leaves into your backwash water because they will be trapped on the underside of the filter and will come back into the pool when you are done backwashing).
  2. Turn the pump off and empty the pump trap basket.
  3. Check to make sure there is not a cutoff valve on the backwash line.
  4. Put the backwash valve on "backwash" and turn the pump on and let it run until the water in the sight glass runs clear. 
  5. Turn the pump off and put the backwash valve on "filter" and run for 10 seconds (if you are using a multiport valve, use the "rinse" setting instead.)
  6. Repeat steps #4 and #5 three more times.  
  7. Turn the pump off and put the backwash valve in the "filter" position.  Turn the pump back on.
  8. When you are done backwashing and the backwash valve is back in the filter position, add the proper amount of DE to the pool by feeding through the skimmer.  Typically this is about one lb of DE per every 12 square feet of filter area. (NOTE: If you have just done a DE clean on the filter, then use one lb. for every 10 square feet of filter area.)  One lb of DE is approximately equal to two one lb. coffee cans.

Do not attempt to move the backwash valve position with the pump running.  Always turn the pump off before moving the backwash valve handle.  Failure to do so can cause serious equipment damage or serious personal injury.

Filter Cleaning Instructions

If the DE filter goes less than 3-4 weeks between backwashing on a home pool, then it may be time for a DE filter clean.  Most filter manufacturers recommend that the DE clean should be done 1-2 times per year.

The filter cleaning process is as follows:

  1. Backwash the filter.
  2. Open the air relief valve so that air can be drawn into the tank and the vacuum inside the tank will be broken.
  3. Remove the top half of the filter.  Normally, there is a band or some other device securing the two halves of the filter together.
  4. Remove the filter grid assembly.  Sometimes it is possible to remove the entire grid assembly, and other times, the assembly is so heavy that it must be disassembled and removed piece by piece.
  5. If the grid assembly was removed intact, disassemble it.
  6. Using a garden hose (and nothing stronger) spray down each piece, removing all the dirt and debris.
  7. It may be necessary to use a filter cleaner to remove oil and dirt from the grids.  Normally, however, a good cleaning with the garden hose is sufficient.
  8. Completely clean out the filter tank.  It is normally a good idea to loosen the bulkhead fittings and physically remove the tank and wash it out.  Clean around the tank body o-ring and make sure the o-ring is in good condition.  When the tank is clean, put it back in position.
  9. Inspect all the parts to make sure there are no tears in the grid fabric or breaks in the grids or upper manifold.
  10. Check the condition of the air relief assembly and make sure it is firmly connected to the upper manifold.
  11. Reassemble the grid assembly and tighten the connecting rods firmly.  Shake the assembly lightly as the rods are tightened to insure that the entire assembly is snug and will not come apart.
  12. Put the grid assembly back in the filter.  Replace the standpipe o-ring if it is missing or badly worn.
  13. Put the top half of the filter back on.  Start up the pump and recharge the filter with the correct amount of DE.