Free Chlorine Vs Total Chlorine Vs Combined Chlorine. When ammonia or organic nitrogen is also present, chloramines known as monochloramine, dichloramine, and trichloramine will quickly form. The key difference between free chlorine and total chlorine is that the free chlorine is the amount of chlorine that can inactivate pathogenic microorganisms present in the water whereas total chlorine is the sum of combined chlorine and free chlorine.
But there’s no test for combined chlorine. Free chlorine is the unused chlorine that’s still free, active, and available to sanitize your water. It is easy to monitor the total chlorine levels, but this measurement is only useful if there is no combined chlorine present.
Nh 3 → nh 2 cl → nhcl 2 → ncl 3.
The level of total chlorine should always be greater than or equal to the level of free chlorine. The goal is to achieve a higher level of free chlorine than combined chlorine. Total chlorine is the combination of free and combined chlorine that is in your pool. Free chlorine + combined chlorine = total chlorine
