Still work in progress setting up my planted 300 L Community Tank, as I live next to a Boulder type river next to the Ruahine Ranges I have a limitless supply of rocks available to decorate the Tank as naturally as I can. Bearing in mind we have a plastic rainwater supply tank, not town water.

Q. what rock types can I use / not use? there is lots of greywacke and deep red basalt, are these ok? should I steer clear of any with white streaks and layers in them (silica??)

Greywacke and basalt should be fine I think. It is limestone you need to watch out for as it leaches and alters the pH. Pour a little vinegar over the rock. If it fizzes, don't use it.

Some white rocks are fine eg marble.

It is times like this I really miss our late member June Goldsack, who was president of the local rock and mineral club. She was a mine (no pun intended) of information.

You'll be able to make a great African Cichlid setup with those rocks!!

It is times like this I really miss our late member June Goldsack, who was president of the local rock and mineral club. She was a mine (no pun intended) of information.

ME ME ME PICK ME!!!!! I study geology starting my 3rd year next year.

As for the question here, NZ is pritty safe ie (other than limestone) all our accessable natural rocks are pritty safe, do the vinigar test, other wise get a rock checked out if it shows any bright colours as these colours can be a product of some nasty things in the rock!

Who ever is in the south island is lucky, you guys have all that shist, and gneiss, granite...all the cool looking stuff!

I'm insulted. At least we share things. We let you guys have the traffic jams.

And apparently from what I noticed last time I was driving in chch, all the turn arrows on the traffic lights too...

On ya bike