Code
Calcium hardness shall not exceed 1000 PPM (MG/L).
Annex
Calcium hardness is the amount of dissolved calcium (plus some other minerals like magnesium) in the water. High calcium is not healthy for swimming since it can cause burning of the mucous membranes, as well as skin irritation on sensitive people. Calcium hardness of 200 - 400 PPM (mg/L) is preferred for proper calcium carbonate saturation and for avoiding soft-water scale found in SPAS and hot tubs when other water parameters are near their nominal levels. For venues with water temperatures greater than 90o F (32oC), the range should be 100 to 200 PPM.
Too much calcium causes cloudiness and scale formation. It also reduces the effectiveness of disinfectants. Too little calcium, especially when combined with low pH or low Total Alkalinity can also lead to “aggressive water,” which can dissolved calcium carbonate from plaster, as well as metallic parts of the POOL (walls, floor, handrails, ladders, light fixtures, and equipment), and also cause discolored water or stains on the POOL walls and floor.
The maximum permissible concentration of 1000 PPM (mg/L) may not be appropriate for regions with particularly hard source water. In such regions local CODES should reflect the specialized practices needed for source waters containing more than 1000 PPM (mg/L) total hardness.
Minor deviations from the calcium hardness levels stated in the CODE do not in themselves present imminent health threats to the BATHERS. As such, minor deviations in hardness levels do not require the immediate closure of the facility. Rather, deviations from permissible hardness levels indicate poor management of the water balance and should indicate a need for a thorough inspection of the entire facility.