Poolside by CGT Pool Liner Care and Maintenance Guide
What Should Pool Calcium Hardness Be?
Calcium hardness is related to the same ‘water hardness’ that can cause scale in sinks and showers. Below hardness levels of 200 ppm (i.e. water too soft), pool water can become corrosive to fittings, fixtures, grout, etc. Above 400 ppm (water too hard), water may become cloudy, or scale can form around the pool and liner. Check and adjust calcium hardness after confirming the alkalinity of the water.
NOTE: The occurrence of scaling may be the result of other factors. If seeing scaling on a pool within the normal calcium hardness range, contact your dealer. Maintaining proper calcium hardness levels in a pool prevents corrosion, scale buildup, and cloudy water.
Target Calcium Hardness
200 – 400 ppm
FAQ
What is the recommended calcium hardness for a swimming pool?
The ideal pool calcium hardness level is 200–400 ppm.
- Below 200 ppm, the water may become corrosive and damage fixtures or grout.
- Above 400 ppm, scale formation and cloudy water may occur.
Calcium hardness should be checked after adjusting alkalinity and should be monitored regularly to maintain balanced pool water chemistry.