Things You Will Need
Alkaline based cartridge cleaner solution, Garden hose, Pressure spray nozzle
The first step is to turn off the power to the pump and filter. Open the pressure relief valve to relieve the pressure from the system. Unscrew and remove the drain plug and drain the water from the filter.
After you have relieved the pressure and drained the water, remove the filter housing and the filter cartridge. Use a pressure nozzle (NOT A PRESSURE WASHER) on your garden hose to remove the loose dirt and debris. Work from the top of the filter down at an angle not greater than 45 degrees. A greater angle or more pressure can actually force the dirt and debris into the filter material. This will break down the filter material and decrease the filters life. Rinse until the water runs clean. The filter does not have to come out white. I recommend that the filter be soaked in an alkaline cleaner solution that is available at your pool supply store at least once a season. You can use a bucket or if the cartridge is too big, a clean trash can works well.
After cleaning the filter, rinse the housing and make sure that the O-ring is clean and in good condition so you can get a good seal when you reassemble the filter. Reinstall the filter, replace the filter housing, close the drain plug, and turn the power back on. Leave the pressure valve opened until all the air is out of the system and then close it. Note the pressure level. When it increases 8 to 10 psi it is time to repeat the cleaning process. When the pressure does not drop after cleaning, it is probably time to replace the cartridge.
Cleaning your pool filter cartridge and providing the proper pool chemical mix is necessary in order to have a crystal clear pool for both enjoyment and to provide a healthy swimming environment for you and your family.
Tips & Warnings
Generally the people working at your neighborhood pool supply store can help walk you through the steps for cleaning your pool filter. They are usually a good source of information for your area.
For your health and safety always keep your chemicals in balance. This along with a clean filter will increase the enjoyment of your pool for years to come.