Balancing Calcium Hardness
Calcium Hardness is important to balance in a spa. Low hardness can corrode the heater and damage the hot tub surface, as well as contribute to excessive foaming. High hardness can cause scale buildup and cloudy water. The higher water temperature of a spa makes it more difficult for calcium to stay in solution, so it is recommended that a chemical product for stain and scale control be used weekly to prevent any scale buildup.
If a water softener was used when filling the hot tub, replace the calcium as soon as possible. Softeners eliminate calcium from the water and can cause equipment damage and surface corrosion. Follow product label or water testing kit for recommendations for the amount of calcium hardness increaser.
Note: This information is intended for a residential spa with average use. It is not designed for public, commercial, or semi-public spas. If your hot tub is used more than three times per week, you should check and make chemical additions more often than suggested.