Definitions for "Langelier Index"
A measure of the degree of saturation of calcium carbonate in water that is based on pH, alkalinity and hardness. If the Langelier Index is negative, the water is corrosive (pH value below 7 or acidic). If the Langelier Index is positive, calcium carbonate can precipitate out of solution to form scale (pH value above 7 or basic). The Langelier Index will vary for cold water and for warm water.
A means of expressing the degree of saturation of a water as related to calcium carbonate ( ) solubility. A calculated number used to predict whether or not a water will precipitate, be in equilibrium with, or dissolve calcium carbonate.
a system for determining the scaling or corrosive tendencies of pool or spa water, by testing the pH, total alkalinity, calcium hardness and water temperature. Each parameter is assigned a value, as per a chart, and is used to calculate the Index. Ideal would be a value of -0.5 to +0.5. Values outside of the range, indicate out of balance conditions and may require chemical treatment. More negative values indicate corrosive conditions. Higher positive values indicate scaling conditions.