Lowering the pH with an acid ...
Published by Pat Stanford, General Manager
Lowering the pH with an acid will convert a portion of the alkalinity (bicarbonate) to carbonic acid. Since there is less free bicarbonate, there will be less calcium carbonate scaling. If Calcium Carbonate is the only issue then you should be OK with just pH adjustment.
But, in most cases there are other compounds (Calcium Sulfate, phosphate compounds, iron compounds, silica compounds) that are also sparingly soluble. Lowering the pH will have no, or very little benefit for these other compounds. If Calcium Sulfate is close to the solubility limit, then adding sulfuric acid will probably make the issue worse. Scale Inhibitors are available the will control all or most of the other compounds.
You need to have a complete water analysis done to properly determine what you need to treat for. Be very careful of anyone who proposes a solution without seeing the complete water analysis.