?????

[penguinpimp1990]

will "red wine vinegar" work on the rock test?.....(the test to see if it contains calcium)

 

[penguinpimp1990]

or does all vinegar work?

 

[Fish Buddy]

probably... all you need is something that is acidic to test if the rock is alkaline. If, when you pour it on the rock, it bubbles that is a reaction between the two sides of the pH scale and the rock is not safe.
If there is no reaction the rock is safe for your aquarium in that it will not raise the pH of your tank.

 

[LoachLover]

Seems like it would work. Edit your post next time instead of double posting