In reponse to recent emails, we will re-visit the topic of free chlorine versus combined chlorine and how they both relate to total chlorine:

(Free Chlorine) + (Combined Chlorine) = (Total Chlorine)

Free Chlorine: Typically your main sanitizing/disinfecting agent and sometimes referred to as ‘available chlorine’. In most cases people try to keep a free chlorine residual in their water to act as a buffer against biological contaminants. Chemically speaking this is the amount of hypochlorous acid and hypochlorite ion in solution. find free chlorine test strips

Combined Chlorine: The resulting compound when free chlorine molecules interact with biological contaminants containing Nitrogen which most people refer to as ‘chloramines’. You could also refer to combined chlorine as ‘used free chlorine’, but keep in mind that it still does have the abiity to act as a sanitizer/disinfectant… just not nearly as effectively.  find total chlorine test strips

Total Chlorine: The sum of all free, ‘available’, combined, and ‘used’ chlorine in solution.  find total chlorine test strips