PH is the measure of acidity in the pool water. PH only ranges between 0 – 14, so even a slight change in the PH of your water can greatly effect various elements in your pool. A pool’s PH should be maintained between 7.2 and 7.6. A low PH means that the water is acidic and will dry out your liner, eat away at any stainless steel and copper parts of your pool, as well as cause irritation to swimmer’s eyes and skin. PH can be easily tested for and is inexpensive to adjust.