Calcium is also in the water, the only time people have to put in calcium is when they use revers osmosis machins or filters. and almost all nutrients have calcuim in them, calcuim defficancy I have never seen even from people running RO systems that do not re add calcium. Almost all nutrients have calcuim in them, I would realy start to look at something elese.

in your water if you take a TDS reading it will be 300 or lower most of that is calcium. when you dont clean the tap for about a month you get water spots and calcuim bulid up, those spots are calcium.