Sulfuric Acid Can Be Used
If the pH level of your pool is too high (over 7.4 or so), you can add an acid to the water to lower the pH. Lower the pH of the water by adding sulfuric acid to the filter pump.
Sulfuric Acid Adds Problems
Sulfuric acid will increase the total dissolved solids level of your pool water and can add unnecessary sulfates. Muriatic acid, which is about one-third hydrochloric acid, will lower your pH without any additional side effects.
You are better off using muriatic acid to lower the pH of your pool water. The sulfuric acid will increase the amount of total dissolved solids in your water and can add sulfates, both of which can cause problems with your pool water.