Why do I have to "shock" my pool water?

The addition of a "shock" product oxidizes (breaks down and destroys) chloramines. Chloramines are formed when nitrogen-containing organic undesirable compounds such as suntan oils, cosmetics, perspiration and others combine with the chlorine in your pool water. The resulting chloramines provide no sanitizing function and actually cause strong chlorine odor, cloudy water and eye irritation.

Chloramines, also known as combined chlorine, need to be broken down or destroyed (oxidized) to produce the active form of chlorine in your pool — free available chlorine. Free available chlorine is the good form that can kill bacteria and algae. So shocking your pool on a weekly basis, or after heavy rain and use, will ensure that a higher level of free available chlorine is available to properly sanitize your pool, keeping it protected from bacteria and algae. The correct level of free available chlorine is between 1.0 – 3.0 ppm (parts per million).

A shock treatment should be a part of your regularly scheduled pool care program, recommended as a weekly application, and applied more frequently after heavy use or rain.