Does lime-soda softening lower the pH of the water it treats?

Lime-soda softening is a water treatment process primarily used to remove hardness from water caused by calcium and magnesium ions. During this process, lime (calcium hydroxide) is added to the water, which helps precipitate out carbonate hardness (calcium and magnesium carbonates) and results in the formation of insoluble compounds that can be easily removed.

One key aspect of this process is that it tends to raise the pH of the treated water rather than lower it. When lime is introduced, it increases the alkalinity and raises the pH to a more alkaline level. In fact, the ideal pH for effective lime-soda softening falls in the range of about 10 to 11.

While it is true that other treatments may lower pH, such as adding acids for coagulation or disinfection, the specific action of lime in lime-soda softening is to raise the pH. Therefore, stating that lime-soda softening lowers the pH is not accurate; it raises it, thus making the answer that asserts it lowers the pH incorrect.