Which scale is used in measuring water hardness?
One scale measures water hardness by solute concentration, in parts per million, milligrams per liter or grains per gallon. Other scales include the Langelier Saturation Index, which considers pH, and the Ryznar Stability Index, which considers salt deposits.References:Fairfax Water: Explanation of Water HardnessNACE International: Langelier Saturation Index (LSI)American Water Works Association: RTW Corrosivity Index CalculatorResources:”Physicochemical Treatment Processes”; Lawrence K.