Assuming that the total alkalinity level is correct, we adjust the pH according to the results of the pH test. Most better test kits have an acid demand test, which allows you to calculate the amount of acid to add in order to correct the pH. You generally need to know the volume of the pool to calculate the quantity required.
In general, the pH of pool water tends to rise. This is a result of chlorination, swimmer’s wastes (sweat, urine) and nature’s tendency to balance the pH of standing water at about 8.5.