? about rocks i just bought

[JStrider]

I'd put this in a tank with a few guppies or something cheap... just to make sure it is safe.

[TaTeR ToT]

i used thye vinegar, and nothing, no fizzing whatsoever.
i will still prob put it in a tank with a few rosy reds just to be sure.

[RMD55]

If it fizzes with vinegar it's not ok for low pH but might be ok for a hight ph Tank.