Calcite is mainly used in water treatment and swimming pools to control both internal corrosion and the deposition of scale. It is used as a neutralizing agent, filler, antacid and Source of lime.

The Langelier Index(LSI)is an approximate indicator of the degree of saturation of water with calcium carbonate. The Langelier Index is one of several tools used by water operators for stabilizing water to control both internal corrosion and the deposition of scale. Water supply operators can optimize their water supply systems and identify leakage potentials with the Langelier Index. It is calculated using the pH, alkalinity, calcium concentration, total dissolved solids, and water temperature of the water sample.

If the Langelier Index is negative, then the water is under saturated with calcium carbonate and will tend to be corrosive in the distribution system. If the Langelier Index is positive, then the water is over saturated with calcium carbonate and will tend to deposit calcium carbonate forming scales in the distribution system. If Langelier Index is close to zero, then the water is just saturated with calcium carbonate and will neither be strongly corrosive or scale forming.

Experience has shown that Langelier Index in the range of -1 to +1 has a relatively low corrosion impact on metallic components of the distribution system. Langelier Index values outside this range may result in laundry stains or leaks.