Guidelines calcium hardness

CH value of less than 100 ppm (mg/l) is described as soft water and draws lime out of, for example,the concrete of cast pools and tile grouting. Water with a CH value above 300 ppm (mg/l) is described as hard water and causes lime to be precipitated.

Low or high CH value makes the water aggressive and the result can be one or more of the following:

• Low value causes disintegration of the concrete
• Low value causes disintegration of the tile grouting
• High value causes limescale on the walls

The calcium hardness can be increased with calcium chloride.

 The calcium hardness can be reduced by dilution with fresh main water. Divide the dilution in stages in gaps of 4 hours. Test the water again and repeat the process until the desired level is reached.

Calcium hardness (pool water)
Minimum: 100 ppm (mg/L)
Maximum: 300 ppm (mg/L)
Monitoring frequency: monthly