Calcium Carbonate (CaCO3) Equivalent
An expression of the concentration of specified constituents in water in terms of their equivalent value to calcium carbonate. For example, the hardness in water that is caused by calcium, magnesium, and other ions is usually described as calcium carbonate equivalent. Alkalinity test results are usually reported as mg/L CaCO3 equivalents. To convert chloride to CaCO3 equivalents, multiply the concentration of chloride ions in mg/L by 1.41, and for sulfate, multiply by 1.04.