Ideal pool combined chlorine range
What is Combined Chlorine?
Combined chlorine (chloramines) is chlorine that has already reacted with sweat, oils, and other contaminants and lost most of its sanitizing power.
Why it matters
High combined chlorine, not excess free chlorine, is the usual source of the harsh "chlorine smell" and eye irritation swimmers often blame on too much chlorine — it typically means the opposite: not enough free chlorine to keep up with contaminant load.
How to raise CC
There's no scenario where you want to raise combined chlorine deliberately — it's a byproduct to eliminate, not a target to hit.
How to lower CC
Shock the pool to breakpoint chlorination (most pool professionals target roughly 10x the combined chlorine reading) to break the chloramines apart and let the residue off-gas.
How often to test
Alongside free chlorine, 2-3 times per week in season, and especially if a chlorine smell or eye irritation shows up despite a normal free chlorine reading.
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Related parameters
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