Limestone in a reef?

[RyanG]

I was looking at some rock on ebay that has wonderful hiding spots and caves but its made of limestone. it says that its saltwater safe but I thought I would ask some people not trying to sell me something. Limestone reef safe or not so much?

I dont want to make a whole reef out of this stuff but I thought that a piece or two would make for some interesting aquascaping heres a link to it.

Texas Holey Rock
http://stores.ebay.com/RockArtSourc...QQcolZ4QQdirZQ2d1QQfsubZ2497538QQftidZ2QQtZkm

 

[Bifferwine]

The exoskeletons of corals are made out of limestone, so I'd say it's safe to use.

In fact, coral reefs are in the simplest terms, limestone formations.

 

[RyanG]

Sweet these rocks are holey as sunday, cove caves nooks and crannys, they are the Thompsons English muffins of Rock. Im gonna have to get some then!

 

[Doc]

cool. post us some pics when you can

-Doc

 

[fatman]

In general most lime stone is fairly pure calcium carbonate, which is made up calcium carbonate precipitate and the skeletons of minute marine organisms that have been under a compressive load for a long period of time. Coral skeletons are aragonite which is a form of calcium carbonate. Aragonite has the same chemical formula as calcium carbonate but a different geometric arrangement of its elements. Aragonite dissolves at a higher pH which is why it is considered better in a tank than calcium carbonate (limestone). There is limestone with fosils in it, typically of marine shells and marine plants. They are tank safe also. There is also oolitic limestone which you can actually see the little round sand grains of oolitic sand. There is also Dolomite limestone, which contains Magnesium. Limestone will not dissolve at normal tank pH's, even those pH's within a deep sand bed. However aragonite will dissolve in the bottom third of a deep sand bed. That is why an aragonite bed appears to settle over time, it is actually dissolving, which is fine as it is full of the trace elements and calcium the corals previously extracted from sea water. In short limestone is safe as long as it contains no other colors in it than white, and there are no obvious bands of different textures of rock present in the lime stone. It is however very dense and therefore heavy and will easily break glass if it falls on it. The rock in the add is not limestone or made of limestone. It is however made out of the same thing as limestone, which is calcite or as the aquarium trade refers to it calcium carbonate. Limestone is a sedementary rock, made up of the calcite sediments. Limestone is a name that is applied to a dense sedimentary rock formed of calcite. The rock you desire and that is advertised really has no formal name yet widely accepted or applied. Some would just say a large porous rock of calcite origins. There is also a wormy version which is really light and porous, but it cost as much as live rock. It is made up of worm tunnel tubes of calcite. OK so I am just a bit over educated, and in strange areas. Check out http://www.mariculturetechnology.com/Rock.htm I am sure they will sell you large pieces at their standard prices, which are a whole lot cheaper than Texas Rock.