Relax pH Plus - pH Increaser - 5kgpH refers to the acidity or alkalinity of the water. When the pH is too high, the water is alkaline not acidic enough. When its too low, its too acidic. Recommended levels for chlorine disinfection are between 7. 4 and 7. 6. Anything outside of this range can irritate swimmers skin and eyes, as well as prevent bacteria from being killed off effectively. If the pH is too low, it can also cause metal fixtures to erode. If its too high, it could cause