I think dosing a solution of ...

I think dosing a solution of dilute hydrochloric acid into the feed water before the cooling tower is a good way to reduce the bicarbonate ion content. This will increase the amount of carbon dioxide in the water. Carbon dioxide will be removed with evaporated water in the cooling tower.

With the effective operation of the cooling tower, the pH of the water will always be at least 8.3 if there is a bicarbonate ion in the source water. Thus, in order to avoid the formation of deposits of solid calcium carbonate, it is necessary to keep the amount of bicarbonate ion in the water of the cooling tower not more than 0.5-0.7 mmol/l. Although it also still depends on the hardness of the source water.

It is important not to reduce the concentration of bicarbonate ion in the source water after dosing the acid below 0.1-0.3 mmol/l (depending on how effectively the cooling tower removes carbon dioxide with the evaporated water).

If the concentration of the bicarbonate ion in the source water is lower, the pH of the water in the cooling tower will be low, which means that corrosion processes are activated.

In any case, it is necessary to control not only the pH of the water in the cooling tower, but also the alkalinity with hardness and salt concentration of water.