Scale Indices

Definition

Empirical indices that estimate how close a water is to conditions under which calcium carbonate scale has historically formed.

Because Ksp is defined in ion activity rather than concentration, the industry uses indices to estimate thermodynamic pressure on calcium carbonate instead. The Langelier Saturation Index, Ryznar Stability Index, and Puckorius Scaling Index are the common examples. They translate thermodynamics rather than replacing it, describe pressure rather than deposition rate, and apply only to calcium carbonate.

Related concepts

Langelier Saturation Index · Ion Activity · Puckorius Scaling Index

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Part of The Blueprint of Water · 📏 measurement