TL;DR
Combined chlorine is the portion of a pool's chlorine that has bonded with ammonia and swimmer waste to form chloramines, compounds that sting eyes, cause the classic harsh chlorine smell, and sanitize poorly. It is calculated as total chlorine minus free chlorine, and a healthy pool keeps it below 0.2 ppm.
What it means
Combined chlorine is the portion of a pool's chlorine that has bonded with ammonia and swimmer waste to form chloramines, compounds that sting eyes, cause the classic harsh chlorine smell, and sanitize poorly. It is calculated as total chlorine minus free chlorine, and a healthy pool keeps it below 0.2 ppm. When the level climbs, service techs perform breakpoint chlorination, raising free chlorine roughly ten times the chloramine reading, to oxidize the compounds and restore water comfort.
Where it sits in the glossary
Combined chlorine is part of the Trade jargon group inside the ProFix Directory glossary. Browse every term in this category from the glossary index.
Why Ohio homeowners should know it
This is a term Ohio homeowners encounter when reading contractor quotes, hiring paperwork, or inspection reports. Understanding it well enough to ask one good follow-up question is usually all the protection a homeowner needs.
ProFix Directory keeps definitions short on the index page and saves the longer context — Ohio-specific rules, where the term comes from, and which ProFix tools touch it — for these per-term pages so the term is easy to cite and easy to share.
ProFix tools that touch this term
See also
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