I seem to recall that others trying doing this and getting "clumping" of their aragonite substrate. Not everyone had problems though. Craig Bingman didn't notice this, I think, partly because his experimental system was in a 100 gallon rubbermade tub and he couldn't really see the substrate (I'm going by my sometimes bad memory)... just a sec let me go search... Check out:
http://www.google.com/groups?as_q=kalk*%20vinegar&safe=off&ie=UTF-8&oe=UTF-8&lr=&num=30&hl=en
Craig answers some of these questions himself. I think Tropic Marin's Biocalcium is a "similar" product. I think it's a calcium acetate salt.