I want to do something with a slate like rock in my tank, I want layers stacked and glued,is slate alright for this?, If not what else could I use and where could I get it from?

i have used sandstone tiles that are available from granite & marble companies

slate works fine, we had some little terraces made up in one of our tanks at work

Yeah, slate should be fine. You don't get much more unreactive than most slate.

Yeah as others said. Alpine schist is good to

Where can I get it from? (in chch)

Should it have white in it? (doesnt that mean lime which will alter the ph??????)

Try landscapers.

And according to the landscape suppliers here the Alpine Schist doesn't have traces of lime.

Halswall quary stone would be good.

The white lines in schist are not lime, they are quartz. This will not alter the pH.