I was looking at some chemicals the other day and saw these 2 ingredients. Can they be used safely to adjust the Ca level? I have never heard of anyone using them.
Calcium sulfate should probably not be used for routine calcium maintenance, IMO. Ocassional use is fine, but not for all calcium supplementatiuon unless the tank has a very low demand for calcium, because sulfate will steadily rise.
FWIW, most salt mixes seem a little low on sulfate anyway, so some use may even be beneficial:
Calcium propionate might be OK, but I'm not certain how fast the propionate will be metabolized. This one will be a balanced calcium and alkalinity additive if all of the propionate is metabolized (as is the case for calcium acetate, which is fine to use, and there is one commercial product: Salifert's All in One).
