I was using it within the chemical context of the pH scale. I was speaking in terms of a pH value of 7.0 being neutral, with values under 7.0 being acidic, and above 7.0 alkaline.
Trust me alkalinity in pool chemistry is a mystery all unto itself. But I wonder if it wouldn’t have common characteristics with alkalinity in other water mediums, i.e. sea water.
Pool Chemistry 101:
Total Alkalinity (TA)
Total alkalinity is closely associated with pH but rather than a measure of hydrogen ion concentration it is a measure of the ability of a solution to neutralize hydrogen ions. Expressed in parts per million (ppm), total alkalinity is the result of alkaline materials including carbonates, bicarbonates and hydroxides - mostly bicarbonates. This acid neutralizing (buffering) capacity of water is desirable because it helps prevent wide variations in pH whenever small amounts of acid or alkali are added to the pool. Total alkalinity is a measure of water’s resistance to change in pH.
Total alkalinity should be maintained in the range of 80 to 150 ppm.
If total alkalinity is too low:
pH changes rapidly when chemicals or impurities enter the water. pH may drop rapidly, causing etching and corrosion.
If total alkalinity is too high:
pH becomes difficult to adjust. High pH often occurs causing other problems such as; cloudy water, decreased disinfectant effectiveness, scale formation and filter problems.