Diatomaceous earth (DE) pool filters have elements that are filled with diatomaceous earth powder that traps tiny dirt particles during the filtration process. When you start your pool filter for the first time, the reading on the pressure gauge is the "clean" reading. When the clean reading raises 8 to 10 lbs. per square inch (psi) over the clean reading, it is time to backwash the pool filter.
Things You'll Need
Diatomaceous earth powder
Empty coffee can
Turn off the DE pool filter. Turn the multiport handle to "Backwash." If you have a slide handle, pull up on the handle all the way. This is the "Backwash" position on the slide handle.
Roll out the backwash hose located on the bottom of the pump. Turn on the DE filter. Run it until the water in the sight glass runs clear or until the water coming out of the backwash hose is clear. Turn off the filter.
Turn the multiport handle to "Rinse." Turn on the pump and run it until the water coming out the end of the hose is clear or until the water in the sight glass is clear. Slide handles do not have this function.
Push down on the slide handle to lock it in place. This position is "Filter." Turn the multiport handle to "Filter." Turn on the pump.
Look at the metal plate, which tells you the size of your pool. It will tell you how much DE powder to add to the filter. One empty coffee can is 1 lb. of DE powder. Fill the can with powder. Open the skimmer cover. Slowly pour the DE powder into the skimmer. If your pool pump requires more than 1 lb. of DE powder, add another coffee can of powder about 10 minutes after the first batch. Keep adding DE powder every 10 minutes until you have added the recommended amount.
Write down the clean reading after you finish adding the DE powder so you never forget.