... Ouch, well if it makes you feel any better when I first started I wiped my biocube and all the inhabitants by adding to much sugar trying to dose a carbon source.
Live and learn, its an expensive hobby and you are taking care of living organisms so always do your research. Mind you that is kind of misleading "Copper safe"
. I would chuck the rock if I were you, it might be more expensive but its just not worth the worry.
Levi