Chlorine is used in swimming pools to kill microorganisms that cause health problems such as diarrhea and ear infections. The amount of chlorine must be raised when a major contaminant such as fecal matter is introduced to the pool water. This process, called shocking, kills biological dangers. Once the process is finished, the excess chlorine must be neutralized before the pool will be safe to swim in again.
Obtain a water sample from a foot below the water's surface in the deep end of the pool. Collect the water in a clean glass jar with a lid.
Test the water sample's chlorine level with a test kit, available at any pool supply store. The optimal range of chlorine is 1.0 to 3.0 parts per million (ppm).
Determine the amount of chlorine neutralizing product to add to the pool, based on the current chlorine level and the number of gallons of water in your pool. Choose from a variety of chlorine neutralizing products at a pool supply store. Each product has instructions for determining proper amounts to use.
Purchase chlorine neutralizer based on the calculated amount required.
Pour the neutralizer into the pool around the perimeter. Begin by using only half of the product you purchased.
Turn on the pool's filter and allow it to run for four hours.
Test the pool water again to ensure the chlorine levels are dropping.
Continue neutralizing the pool until chlorine levels fall in the proper range.