As was mentioned during the discussion of calcium carbonate scale, sulfuric acid reacts with calcium bicarbonate by the following reaction:

Ca(HC0₃) + H₂S0₄ ——————> CaS0₄ + 2C0₂ + H₂0

By neutralizing some of the water's alkalinity with sulfuric add, it is possible to operate the cooling system at higher cycles of concentration without exceeding the solubility of calcium carbonate. However, even though the CaSO4 formed is 100 times more soluble than CaC03, it is important to still refer to CaS0₄ solubility curves to ensure that the water is not oversaturated with CaS04.

By far, sulfuric acid is the most frequently used acid for alkalinity neutralization. However, there are several other adds that are sometimes used. The following is a brief description on some of these.