DE swimming pool filters use filter screens and diatomaceous earth to keep water clean. Use the following steps to pre-coat a Haywood DE-4800 swimming pool filter following a back flush and rinse, a manual cleaning, or a repair. Haywood models DE-2400, DE-3600 and DE-6000 are similar to the DE-4800.
Turn off the pool pump and rotate the skimmer/sump control valve so that only the skimmer is being used to draw water back to the pump. The valve should be rotated to only draw from the skimmer.
Once the surface skimmer is drawing water you should see the flapper valve leaned over. Remove the basket from the pool skimmer.
If you have solar panels, turn off the power to the solar control panel. The electrically operated valve that allows water to flow to the solar panels should be closed. If you have another manually operated valve that controls water flow to the solar panels, close it, too. You do not want to get the DE in the small tubes that run through the solar panels.
Turn on the swimming pool pump and quickly scoop 6 pounds of DE into the pool skimmer. (Model DE-2400 uses 3 pounds DE-3600 uses 4.5 pounds DE-4800 uses 6 pounds DE-6000 uses 7.5 pounds.) Since the pool has been set to use the skimmer to draw water back to the pump, the DE is quickly drained from the skimmer and coats the filter screens. Be careful not to breathe the DE.
Turn off the swimming pool pump. Reset the skimmer/sump control to its normal position. Clean and replace the skimmer basket, and restart the pool pump.