I happen to collect some stones at a local creek and did some rockwork for my tank (see gallery) The look of the tank changed since, gone is the lighthouse, the skull, there are some live plants, but back to topic.
I have scratched those rocks and used vinegar and acetic acid to test for calcium deposits, negative. Yesterday I bought Nitrate test kit and bottle #1 is acid of some sort. I tested a couple of rocks and in some parts of them they fizzled like crazy! No wonder my tap water is 7.0 - 7.1 and my aquarium water is 7.6 stable. Do you think I should take them out and replace them with non-calcium ones? there will be no cichlids in the tank, just community, angels, loaches, corys, maybe assorted mollys. It provides a nice buffer against PH
drop from decomposition, but isn't it a little too much of a buffer? Share your thoughts and test your rocks!