pH control is to reduce ...
Published by Clive Ling, Technical Consultant at Nalco Water, an Ecolab Company
pH control is to reduce bicarbonate alkalinity and the increase the solubility of calcium hardness. If pH is controlled automatically with a pH controller, at pH 7.2, usually acid feed is automatically stopped. Most control ranges are between 7.5 and 8.5. Lower than that is for phosphate control to increase the solubility of tri calcium phosphate.
Hence, one has to know the saturation limits of the makeup minerals involved. Nowadays, calculation of limits is doen with software. The anti-scalant vendor can help calculate the pH set points.