Your swimming pool's filtration system is your first line of defense against algae and bacteria, so it's essential that you keep it in good running order. One of the most important maintenance procedures that you must perform is to periodically backwash the filter. The process of backwashing knocks loose particulates that may have become lodged in your filter and ultimately assists your filter in operating more efficiently. The following instructions are for backwashing a D.E. (or Diatomaceous Earth) pool filter.
Locate the power supply for your filter. Turn the on/off switch to the off position.
Adjacent to the filter is a multiport valve; locate this, and turn the handle to the backwash position. Adjacent to this is an external backwash valve, the handle of which you will turn to the open position. The backwash valve moves the water through the filter to wash the particulates loose, and then expels the water via the backwash hose.
Turn the on/off switch back to the "on" position so that the filter is now running. The backwash valve is now running water through the filter, dislodging soils, and expelling the waste water via the backwash hose.
Connected to the backwash hose is a clear viewing window that allows you to see the water being expelled from the filter. When this water runs clear, the first step of your backwashing is complete, and you may stop the filter.
Turn the backwash valve back to the filter position and run the filter as normal for 1-2 minutes to further dislodge any particles and the existing D.E. At the end of the allotted time, turn the filter off again, and return the backwash valve to backwash and allow it to run for another minute.
Once the latest backwash cycle is complete, turn the filter off. Close the external backwash valve, and return the backwash valve to "Filter." Return the filter to the "on" position.
With the filter running, locate the pool skimmer nearest the filter. Add an appropriate amount of D.E. to your skimmer -- most agree that 3 1 lb. coffee cans full is sufficient. Add additional water to the pool as necessary, depending on the amount of water that you have emptied from the pool. Depending on the degree of cloudiness or "green" of your pool, it may be necessary to repeat the backwash process several times.