Quote Originally Posted by waterbear
Biggest problem with calcium cabonate is the solubilty vs. calcium chloride. Calcium carbonate is also what we call "scale deposits" and if you have ever has them on your tile line you KNOW that they are hard to remove

Not sure I follow why this would be a problem, if you need calcium. The CaCO3 should dissociate and just result in CO2 off gasing assuming you don't add more than is needed.