Alkalinity (as CaCO3)

Alkalinity is a key measure of a water sample's general chemistry. Alkalinity measures the capacity of water to neutralize acids. Alkalinity is thus indicative of the stability of a water sample's pH upon the addition of acid; water with higher alkalinity will maintain a stable pH after the addition of more acid. Water with low alkalinity cannot buffer against such changes and can therefore become acidic and potentially corrosive to plumbing.The vast majority of alkalinity comes from dissolved carbonate and bicarbonate, though other compounds, like phosphates and borates, contribute minorly to alkalinity.