About This Item HTH pH Down helps balance pH levels in swimming pool water improving both the quality of the water and the comfort of your swimmers. pH down not only ensures that your chlorine is working more efficiently but it helps prevent scale formation on pool surfaces and equipment as well as significantly reduces skin and eye irritation. HTH pH Down is great for all pool types including vinyl lined pools and salt water systems. How to Use HTH pH Down Use HTH 6 Way Test Strips or Test Kit to test your water weekly to make sure the pH level is between 7.2 and 7.8 ppm. If the pH measures above 7.8, add HTH pH Down directly to the pool water to decrease the pH. Swimming can resume immediately after treatment. About HTH Pool Care HTH was developed with the pool owner in mind. We know that maintaining your pool water can be a lot of work. That is why we are here every step of the way helping you clear the uncertainty from pool care. With economical easy to use solutions HTH is designed to work hard so you are prepared to tackle whatever life throws in your pool. From balancing your water to treating green water we offer a full line of products to keep your pool water healthy and your swimmers happy.