Chlorination is one of sterilization method in drinking water and industrial water, and chlorine measurement is very important to secure water quality. We provides two type of chlorine analyzers, non reagent type chlorine analyzer for free available chlorine measurement and reagent type chlorine analyzer for free chlorine or residual chlorine (total chlorine) measurement. You can find the best solution thanks to unique Apure technologies proven by experiences.

chloride ion selective electrode product 3 — CLI-406 Chloride Ion Selective Electrode

What is Residual Chlorine?

“Residual chlorine”, generally referred to as “free chlorine”, refers to chlorine in the form of hypochlorous acid, hypochlorite ions and dissolved elemental chlorine. Its synonyms are “free residual chlorine“, “free chlorine” and “free residual chlorine”.

The opposite of “free chlorine” is “combined chlorine”, which is chlorine in the form of chloramines and organochloramines. Synonyms for this are “compound residual chlorine” or “compound residual chlorine”.

And “total chlorine” and “total residual chlorine” are synonyms, refers to “free chlorine” or “combined chlorine”, or both of the form of chlorine, can be regarded as the water “free chlorine” and “combined chlorine” the sum.

To sum up, there are three disinfectant indicators related to chlorine disinfection:

Synonyms for residual chlorine: free residual chlorine, free chlorine, free chlorine;
Synonyms of combined chlorine: combined residual chlorine;
Total chlorine synonyms: total residual chlorine.

For the same water sample, the relationship between the contents of the three indexes is as follows:

Residual chlorine + combined chlorine = total chlorine