Today’s Pool Chemical Tip: Combined Chlorine. Combined chlorine occurs when free available chlorine combines with ammonia or other nitrogen containing contaminants present in pool water. Combined chlorine (or chloramines) is not an effective sanitizer for pool water applications. Combined chlorine can contribute to cloudy water, chlorine odor and eye irritation. The only way to find your combined chlorine level is to test for total chlorine and free chlorine, then subtract free chlorine from total chlorine. Removal of combined chlorine is achieved through a process known as “breakpoint”. “Breakpoint” oxidation is used for the specific purpose of destroying combined chlorine. The most common choice of oxidizer for residential pools is chlorine. To achieve “breakpoint” chlorination, 10 parts per million (ppm) of free chlorine must be added for every 1 ppm of combined chlorine. This is an “all or nothing” process. The entire amount of chlorine chosen must be added in order to reach “breakpoint”. It is always best to round up the amount to insure that “Breakpoint Chlorination” is achieved. There are several websites available to walk you through this process. For more information, please contact Laurie at The Pool Man, Inc, and she will be glad to help you. For more pool chemical tips from your Pool Builder in Houston, please check out our blogs.