Sirona Spa Care pH Balance + is the must have chemical to lock in a proper pH level in your spa. This product will last from refill to refill, and will lower the amount of regular pH adjustment treatments. It is compatible with chlorine, bromine, ozone, and mineral purification systems, and it can even be used with hard water sources. Using this product to help maintain properly balanced water will prevent staining, scaling, equipment corrosion, and skin and eye irritations.