A water treatment system includes a weak acid cation resin where a portion of the feed water is exposed to the resin and then blended with untreated feed water to produce a stream of water with reduced mineral scaling and potential. Feed water is split into a first fluid stream, fed to a bypass conduit and a second fluid stream that is conveyed through a weak acid cation treatment bed. After passing through the bed, the treated fluid is combined with the bypass fluid stream to produce a blended feed water at the outlet. The ratio of the bypass fluid stream and treated fluid stream is a function of pH and L.S.I. A controller and associated sensors may control the relative flow rates between the bypass fluid stream and the treated stream to maintain a predetermined water parameter such pH, L.S.I., etc. within a predetermined range.