Water having alkalies selected from sodium, potassium and mixtures thereof dissolved therein is treated with a composition to reduce the concentration of the alkalies whereby the water is rendered usable according to ASTM standards to render the water usable as concrete mix water. The composition and the method of its use is disclosed herein, wherein the composition is selected from compounds in the group consisting of lithium carbonate, acid zirconium phosphate, carbon dioxide and mixtures thereof.