แคลเซียมคลอไรด์ 5 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.

The correct level of calcium hardness i between s 175 and 275 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.