Check the listing for details. Sirona Spa Care Calcium Booster - 4 Pack. Condition: New. Listed at 43.96 USD. Sirona Spa Care Calcium Booster efficiently increases calcium levels in spa water, preventing equipment corrosion and foam formation. This granular balancer is safe for use with various sanitizers, helping maintain a calcium range of 200-400 ppm for balanced water. Product Features: The calcium increaser for hot tub raises calcium hardness in spa water quickly, so you can focus on whole-self wellness Prevents foaming and equipment corrosion for a clean, soothing spa experience Liquid solution boosts calcium with this fast-acting and easy-to-use formula Calcium increaser for hot tub keeps spa water between 150 and 400 ppm for clean, beautiful spa water you can relax in Unique liquid is compatible with chlorine, bromine, ozone and biguanide sanitizers Directions: Test your water's calcium hardness every week with the Sirona Test Strips and adjust accordingly. Add appropriate amount of Sirona Calcium Booster as designated by the table below to maintain the spa water calcium hardness within the 200-400 ppm range. Circulate spa water on high speed for a minimum of 15 minutes.