If the pH of your spa water is above 7.6, use Arctic Spas PH Adjust Down to lower it. Spa Adjust Down can also be used for lowering total alkalinity if it rises above 150mg/l (ppm). To lower the pH, add 17g of Adjust Down per every 1,500 litres of spa water. Run your pumps for 30 minutes and the test the pH level again. Repeat the process if the level is still too high.