Shut down the pool pump. Turn the control valve handle to "Backwash," or pull up on the handle on the valve control with only two positions. Roll out the backwash hose connected to the bottom of the pool pump.
Turn on the power to the pump and run for two minutes or until you see clear water running out of the backwash hose. Shut the pool pump down when there is clean water running out of the hose. If you have a slide valve handle with only two positions (filter and backwash), skip to Step 5. If you have the valve handle with only four positions (backwash, waste, filter and pool boost), skip to Step 4. If you have the valve control handle with six positions (backwash, rinse, filter, waste, recirculate and closed), go to Step 3.
Move the valve control handle to "Rinse." Turn on the power to the pump and run for 20 seconds. Shut down the power to the pump.
Turn the valve handle to "Filter" on the four- and six-position valve control handles and start the pool pump. Follow Step 5. Leave the handle in the up position (Backwash) on the slide valve handle with two positions and follow Steps 5 and 6.
Add the diatomaceous earth powder to the skimmer basket quickly. The powder travels through the filtering system and coats the D.E. filter inside the pool pump. Add the recommended amount of D.E. powder for your specific model of pool pump, which is located on the cover of your pump manual. For instance, Model DE2420 uses 3 lbs. of product and DE7220 uses 9 lbs. of powder. It is vital to the system to add the correct amount.
Turn off the pump after the powder is added on the pump with the slide valve handle with two positions only. Push down on the handle so it is in the "Filter" position. Turn on the pump.