Bobs_spa

I have a consistent problem with my spa water treatment. My starting water has Calcium Hardness of 55ppm and pH of 6.8. I raise the Calcium Hardness to 300+ppm. This leaves the water with good Total Alkalinity of 80-120ppm - perfect. So I then correct the pH upward incrementally by adding Sodium Carbonate. As I add each 1-1.5oz increment of Sodium Carbonate, the Total Alkalinity moves up and the Calcium Hardness goes down, and the water gets cloudy for several hours. I assume the cloudiness is due to Calcium precipitate of some kind. I assume that the precipitate is filtered out or sticks to spa surfaces. Once the pH is above 7.2, the Total Alkalinity is above 120ppm and the CALCIUM HARDNESS IS LOWER THAN IT STARTED AT BELOW 55PPM!!! I then start over and raise the calcium hardness again and then have to raise the pH again, which has dropped to 6.8-7.0. Then the Calcium Hardness goes back down and the alkalinity goes up. IT IS A VICIOUS CIRCLE!! Should I be using something else to keep the Calcium in solution, or should I try SODIUM HYDROXIDE TO RAISE THE pH INSTEAD? I use a digital meter to get my readings, so judgement of colors on sticks is eliminated. PLEASE HELP.