sanstone for brackish tank?

[susiejames101]

Hi
My LFS has got some really pretty multi coloured rock ( shades between cream to brown) with a very sandy feel to it which also has holes drilled into it, and I am sure my F8 would love to play in it. I asked what the rock was and was told it was sandstone and when I asked if it would be suitable for a brackish tank the guy said it would be perfect for a brackish tank as it would keep the PH up,
Not that I am cynic or anything but I have been told things in LFS's before only to find out it was total twaddle so I was wondering if anyone knew if sandstone was good or bad for a low end brackish tank
Ta
Sue

[Corvus]

Sandstone is ok for low end brackish. But most sandstones consist almost exclusively of quartz (SiO2), which does nothing at all measurable to the pH.

Carbonate rocks (ocean rock, reef rocks) can buffer the pH.

[Nick]

Some sandstones contain enough lime to buffer the PH, but most likely they are confusing them with Tufa stone, which WILL buffer PH, and looks a bit like corroded styrofoam. I have a big tufa rock in with my baby Shakespeare and he likes swimming around and through it, all the little crannies seem to stimulate him to search it for worms/snails.