TL;DR
The Langelier saturation index is the calculated measure of pool water's calcium carbonate balance, combining pH, temperature, calcium hardness, total alkalinity, and dissolved solids into a single number where zero is balanced, negative values mark corrosive water, and positive values mark scale-forming water. Plaster, grout, and heat exchangers dissolve under sustained negative readings, while positive ones cloud water and crust tile lines.
What it means
The Langelier saturation index is the calculated measure of pool water's calcium carbonate balance, combining pH, temperature, calcium hardness, total alkalinity, and dissolved solids into a single number where zero is balanced, negative values mark corrosive water, and positive values mark scale-forming water. Plaster, grout, and heat exchangers dissolve under sustained negative readings, while positive ones cloud water and crust tile lines. Service techs target roughly minus 0.3 to plus 0.3, and the index explains why pH alone can look fine while surfaces still etch.
Where it sits in the glossary
Langelier saturation index 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.
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See also
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