Pool Water Chemistry
What Is Parts Per Million?
Parts per million expresses a small concentration as one part of a substance per million parts of the mixture.
Understanding the Concept
For dilute pool-water measurements, one part per million is approximately one milligram per liter. The approximation depends on water density.
Common Misunderstanding
The substance and reporting basis matter: calcium hardness reported as calcium carbonate is not the same as the mass of elemental calcium.
Related terms
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