Flagstone in a south america biotope

[Akira]

Hey,

I am going to try and create a south america biotope in a 48 US gallon tank. I intend to use a LOT of flagstone to create a rocky piece that will seperate a section with sand from a section with gravel. I was wondering though, is flagstone suitable for this biotope? Is there lime/calc in flagstone that would make the water too hard?

Akira

[NorthernBoy]

Flagstone is perfectly acceptable. It is a just the name for Penn. Bluestone. They are both fancy Landscaping names. It contains feldspar which gives it the blue color. Flagstone is a sandstone which makes the rock essentially quartz. My tank is full of it.

[Akira]

Actually, the flagstone they sell over here is also availiable in red, black, green, all sorts of variations in color. It's all sold as flagstone, and all the same material, just different colors.

[NorthernBoy]

The material that binds flagstone is usually composed of silica, calcium, or iron oxide. The color of the rock usually comes from the cementing material. Typical colors of flagstone are red, blue, buff, and there are exotic colors like chocolate. It is often used for patios, walkways, steps, fences, housing, and many construction projects. I only use the natural gray.