I heard that using a drop or two of API Nitrate bottle # 1 on rocks is a reliable test to determine if they are aquarium safe (inert). Is this true?
I read that vinegar is not really a strong enough acid. I will try both when I find a stone that fizzes with the nitrate test drops.I have heard that too I just dont remember if it was 1 or 2...lol Vinegar is cheaper I say.
Good idea.Tossing the rocks in a bucket of old tank water is one way to see if the PH changes after a fortnight.
Sorry I don’t know if what you ask is reliable.
At most I would use it as a guide?