For what it's worth, I'm still dripping Kalk and Vinegar in all of my makeup water, and have encountered no problems attributable to this practice.
I use 25ml of 5% Acetic Acid for each 1/2 teaspoon of Calcium Hydroxide per liter (quart) of RO water. (Four times what tetra reports using.)
When you mix the Calcium Hydroxide into the Acetic Acid before adding the water, you consume all the Acetic Acid into Calcium Acetate. Since the Acetic Acid is the limiting reagent, there is no potential for any leftover free Acetic Acid that would enter the tank and cause problems with anything else.
The pH of the resultant solution is always well above 8.3, so there is no possibility of acid/metal reactions occurring in the tank. I cannot envision anyone INTENTIONALLY using enough Acetic Acid in their Kalk mix to exceed the Calcium Acetate endpoint.
Excess leftover free Acetate ions are the one real possible source of trouble, if your biological filtration (live rock and live sand) is not working sufficiently to utilize it as nutrition. (If your Nitrate levels are under control, you know you are in good shape in that area.)
The chemistry here is well understood and deterministic -- there is nothing else going on beyond what is claimed. It may be difficult for laymen to believe, but if inorganic and organic chemistry were not exact sciences, most of modern industrial and consumer society could not be sustained. Chemistry works the same every time -- it is not Alchemy or Witchcraft.
By the same token, since there is no magic going on here, as pointed out by someone else above there is no reason to play around with Vinegar if
B-Ionic or just plain Kalkwasser is enough to maintain the Calcium levels in your tank.
Adding Vinegar in Kalk is a means to an end, not an end in itself. It's too valuable a tool to be discredited by injudicious use or anecdotal claims of undesirable side-effects, and I hope it does not become a "reef fad." We have too many of those already.
I do, by the way, use lab-grade chemicals, which are both less expensive per unit, and of more certain content, than pet store or grocery store items.
Back when I used Kalkwasser mix I always used Kent brand, and when I used food-grade white vinegar I used Heinz brand. I never had problems with impurities. I never tried grocery store Pickling Lime.
Although it should go without saying, never use anything but pure white distilled Vinegar. If you add apple or red wine or other flavored Vinegar to your tank you are on your own.
The only reliable reports I have seen of problems from adding small amounts of Vinegar in Kalk that were not clearly attributable to blatant "oper
ator error" involved off-brand or grocery store label Vinegars that had sugar added but not listed on the label. A taste will tell you.
Those concerned about purity and who can't buy lab-grade chemicals locally can buy the required reagents on-line from someplace like Redbird Services or the Science Alliance. Such places sell a lot of other pure chemicals that are very useful in reef keeping too, and are good resources to know about in general.