Pool shock is fluid or granular chlorine. One needs to add one gallon or one pound of pool shock per 10,000 gallons of pool water each week to about fourteen days. During the hot climate or when we are using the pool more frequently, more pool shocks are required. Low chlorine levels regularly cause green and Cloudy water so if your water looks somewhat shady and you utilize pool shock, adding the shock to the pool is the initial step. It is in every case best to use the pool shocks in the evening when the sunsets. If not, the sun will suck it out as quick as you add it.