How to clean rocks for tank

[snitz55]

I bought some rocks at the pond store, as it is cheaper then the LFS, to make caves for my fish. Of course the pond rocks are not sterile. I scrubbed them with a brush and water and have them soaking in water at this time. You think they will be okay to put in my aquarium.

[OrionGirl]

If they are made of an inert substance, like granite, then yes. If they are sandstone or limestone, then maybe not--they will dissolve and alter the water chemistry. This would be fine if this is an African cichlid tank, though.

[snitz55]

It is slate, river rock and flagstone

[daveedka]

Slate will be fine, river rock will need to be checked, and Flagstone will need to be put out back to stand on when the yard gets muddy.
Flagstone is usually limestone, and one of the no-no's You might test it the same as the river rock, but the cances are slim that it is anything but lime.
River rock could be anything, I personally collect a lot of rock and after cleaning I soak them in di water for a week and test the water to see if it changed. you can also pour vinegar over them and listen for a fizzing noise, if it fizzes it will alter your tank water.
Slate is good and stable, and should pose no problems.
dave

[snitz55]

Okay thanks for the info,,,I poured vinegar on what the lady at the pond shop called flagstone and there was no fizzes,,,so I guess it is something else...looks to me to be some type of quartz or granite but I'm no rock expert. I got them soaking in a tub of water and I'll check the ph in a couple of days and right before I add them to tank. Won't be for a couple of weeks though just to be sure.