5 Steps to Shock a Pool to Breakpoint Chlorination

Test your water first Find the combined chlorine level by subtracting free chlorine from total chlorine. Multiply that number by 10 to determine how much shock you need.

If you don’t know combined chlorine, target 10 ppm free chlorine For a typical 20,000 gallon pool, add about 2 gallons of 10% liquid chlorine or one pound of calcium hypochlorite shock per 10,000 gallons.

Shock at night Sunlight burns off chlorine quickly. Apply the shock after sunset to prevent UV degradation.

Run the pump overnight Circulation helps the chlorine react fully with chloramines. Test the water the next morning.

Check for success If the water smells like clean chlorine (not a locker room odor) and looks sparkling instead of dull, you hit breakpoint. If it still stinks, repeat the process.