Total Chlorine
Total chlorine is the sum of free chlorine and combined chlorine in pool water.
Definition
Total chlorine is the sum of free chlorine and combined chlorine in pool water.
Typical Values: Should equal or closely approximate Free Chlorine (FC) in well-maintained water
In Plain Language
Total chlorine is measured by DPD-3 tests or OTO tests. It tells you the full amount of chlorine-related compounds in the water but does not distinguish between the active sanitiser (free chlorine) and the inactive by-products (combined chlorine). When free chlorine equals total chlorine, there is no combined chlorine in the water.
Why It Matters
Total chlorine alone is not a useful management number — you need free chlorine and combined chlorine separately. However, combined chlorine can only be calculated if you have both free and total chlorine readings.
Typical Values
Should equal or closely approximate Free Chlorine (FC) in well-maintained water
Last reviewed: 2026-06-01