SHOCKING is adding enough chlorine to increase the Free Chlorine to 10 PPM for at least 4 hours.

Periodic shocking will help prevent the buildup of Combined Chlorine, organic wastes and algae growth.  However, if you pay close attention to daily free chlorine levels and combined chlorine levels you will have to shock your pool less often.  Routinely shocking your pool once a week can make up for sloppy chlorination.

If you do not want to test for combined chlorine you can routinely shock your pool once a week when the water temperature is over 85 degrees.  When the water temperature is 85 degrees or less you can shock once every 2 weeks.

Additional shocking is necessary under high bather load or rain.

After shocking you should not use the pool or spa until the chlorine levels return to normal.