About This Item Low alkalinity levels in spa water can cause undue damage to surfaces and equipment. HTH Spa Alkalinity Up not only raises the total alkalinity in your pool water, but it also helps keep the pH levels from fluctuating. This helps prolong the life of spa surfaces and equipment, like filter systems, and ensures healthy, comfortable water by protecting against skin and eye irritation. HTH Spa Alkalinity Up is compatible with all sanitizers including bromine, chlorine and biguanide. How To Use HTH Spa Alkalinity Up Use HTH Spa Test Strips to test your spa water. If the total alkalinity level measures below 80 ppm, apply HTH Spa Alkalinity Up directly to your spa water. Refer to on-pack instructions for the correct dosage. Allow water to circulate for 1-3 hours. Test and repeat as needed to maintain total alkalinity levels between 80 and 120 ppm. About HTH Spa Care For generations, HTH has been leading the way in smart spa care. We do the chemistry so you can just take it easy. From the very first day you open your spa, HTH is here to help maintain and problem solve. Our complete range of simple-to-use, no-nonsense products empower you to balance, sanitize and treat your spa-it's everything you need and nothing you don't. There is nothing more relaxing than taking it easy in sparkling, clean water. With HTH, your spa is always ready when you are.