Aquarium rocks (yeah, it rocks but I am talking stones here)

[captainGregor]

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!

 

[Sati]

Obviously nobody will live by my words, but I love rock! I bring it home from the beach and from the creek. I just added about 40 lbs of rock to my tanks and my fish are doing awesome. I soaked them in a very light bleach treatment and then boiled the rocks. They look beautiful and provide great hiding spots. I've done this for years and never lost a fish or had any problems.

 

[possum]

FWIW i dont really think 7.6 is too high of a ph for any of the fish you listed....people will tell you angels need low PH but i have found that they do just fine as long as they arent shocked by a drastic change in the PH. And also those mollies will do better in higher PH than lower