Volcanic Rock

[Aqua]

Does anyone know if good ol' Auckland volcanic rock is inert? Or if not, what effect it does have on an aquarium? I'm contemplating heaving a large chunk of it into my community tank, as it has all sorts of lovely little holes for the fish to investigate, and I want to know if it'll kill my tank or not! :lol: :roll:

[Matthew]

remembering back to school days volcanic material is inert. don't quote me, but I would be keen to put it in a tank. however make sure the rock isn't to sharp, as this could have implications later on. i.e. loss of scales etc

[andyman98]

i have just been doing volcanoes in science and yes it should be inert.you can always pour vingar on to see if it bubbles.

[Warren]

Volcanic rock is usually very hard and the rock is inert. However, many volcanic rocks are very porous (pumice and scoria are examples). The fine pores can contain large quantities of toxic materials. It is always a good idea to soak the rock in fairly strong Hydrochloric Acid (>5%) for a couple of days followed by a very thorough wash. It then needs to be soaked in a weak baking soda solution to kill the acid stuck in the pores - another day. Give it a good rinse and it should be ok after that.

If you are worried, put it into a spare tank and add a couple of tester fish. If all is ok for a week or two will probably be alright.

Porous volcanic rocks are formed by gases blasting through the rock as it flies out of the volcano. The gases are very toxic containing many sulphur compounds, gaseous metals and heavy metals. If there are deposits inside the rock they could hurt your fish.