แคลเซียมคลอไรด์ 18 Kg

Water is "hard" when calcium is present in high levels. In-ground pools are susceptible to damage from calcium salts in the water. If the calcium levels are too low, water can leach the mineral from the pool walls, and damage the grout. Scale forms when the levels rise too high; the water clouds and metal fixtures might corrode.

Calcium chloride is used to increase the water hardness in swimming pools. This process reduces the erosion of the concrete in the pool. By Le Chatelier's principle and the common-ion effect, increasing the concentration of calcium in the water reduces the dissolution of calcium compounds essential to the structure of concreteCalcium chloride is an inorganic compound, a salt with the chemical formula CaCl2. It is a colorless crystalline solid at room temperature, highly soluble in water.

The correct level of calcium hardness i between is 150 and 200 ppm for concrete pools and 80 to 150 for vinyl-lined pools.

To raise the level of low calcium add calcium chloride. Divide the amount of chemical to be added into three parts. Add the first part to the pool and circulate the water for at least four hours.