Limestone Rock

[Guy W]

hey all, quick question. I live in South Florida and I have access to a limestone rock querry (sp?). I can pick the limestone rock up by the truck load if I want, but I don't know if it's safe to use in reef tanks.

Also if it's safe, are there any pro's and con's to using it over Fiji Rock? Aside from the obvious visual differences?

Anyone have any thoughts on this?

Thanks,
Guy

[mogurnda]

I haven't done the experiment, but I would think that limestone would be a lot more dense and less porous than Fiji live rock, or even the dead coral that they use for aquacultured live rock. I'd say that there's not much hazard, but you might not get good denitrification.

The other possibility is phosphate leaching. Might be worth putting some in a bucket of water and testing for PO4.

[wayne]

It totally depends on the limestone. If it feels heavy, is dense non porous or a chalk it's porosity is likely close to nil and it will be pretty poor. Alternatively it might be a light, porous reef or oolite based rock that might be a good alternative to base. Limestone is a total bucket term - it might be even be a dolomite with a higher Mg content or an aragonite not calcite limestone.

[a_free_bird73]

If it is dense and heavy then it will be useless from a denitrification point of view. However, I do use this type of rock instead of coral base rock to build my base structure and then put corals or live rock around it and you can't tell the difference

For me advantages are it costs nothing, will buffer water pH in the same manner as coral rubble, offers a much more rigid structure that large snails and other disruptive organisms can't move and also you can find virtually any shape and size you want so you can build structures that are other wise diffecult to get suitable live rock for.

Disadvantages are, it adds a lot of weight, so you have to be careful on how you arrange it and try to minimise stress on the glass bottom, it is useless from denitrification point of view (but that is not really an issue beause you can still get enough rock around it)