There are no chemical products available to lower your calcium level. Either, run your fill water through a water softener or drain 12” of water from your spa, refill, and retest. A third alternative is to have water delivered but make certain the new water has a good hardness level. Another solution that sometimes works is to lower the alkalinity. Yes, it will lower the pH, but it should rise on its own as the hardness level drops. Also, correcting pH and alkalinity levels and using a “HT Mineral Purifier Stick” will assist in preventing scaling without softening your water.