This pool shock has the highest chlorine percentage (65%) amongst all chlorine pool shocks.
Use calcium hypochlorite if you need to add calcium into the pool water. It needs to be pre-dissolved before it is used to shock the pool.
Use it at night or in the evening to protect free chlorine from UV light from the sun.
Also important, you need to wait for 8 hours before using the pool when you use calcium hypochlorite to shock a