Total Alkalinity Plus is used to increase the Alkalinity of your spa water Spa water tends to lose Total Alkalinity (TA) within days of you filling your spa with fresh water Low TA will result in damage to your spa equipment, pH fluctuation and bather discomfort. Ideal levels are between 100 parts per million (ppm) and 140 ppm. Test the Alkalinity of your spa water at least twice per week, more often if you are located in a soft water area