WHAT ARE TOTAL, COMBINED AND FREE CHLORINE?
These are states of existence for the chlorine molecule. If a molecule is “free”, it has not bonded with another compound, and is therefore available for sanitizing. When free chlorine molecules encounter and destroy a nitrogen or ammonia-containing compound, they combine with them to create a “combined” chlorine compound (also called a chloramines). The chloramine is no longer available to sanitize anything, and it blocks the path of free chlorine molecules, and creates the strong odor associated with chlorine. Combined chlorine level can be tested with a test kit that measures total & free levels separately, and allows the tester to determine combined levels by subtracting the two values. “Total” chlorine is simply the sum of combined and free levels.
