# Diatomite as substrate



## egementt (Jun 27, 2006)

I'm thinking of using diatomite cat litter as substrate. What do you think? Its very porous, lightweight and seems inert. Its used in horticulture. I would really appreciate your knowledge and experiences.


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## Laith (Sep 4, 2004)

I don't know about a cat litter variety but isn't this the same stuff that is used as a filtration material to "polish" water (DE)?

Here's a definition I found from http://minerals.usgs.gov/minerals/pubs/commodity/diatomite/:

"Diatomite is a chalk-like, soft, friable, earthy, very fine-grained, siliceous sedimentary rock, usually light in color (white if pure, commonly buff to gray in situ, and rarely black). It is very finely porous, very low in density (floating on water at least until saturated), and essentially chemically inert in most liquids and gases. It also has low thermal conductivity and a rather high fusion point. Diatomite is now used principally as a filter aid; but it has many other applications, such as an absorbent for industrial spills and as pet litter, a filler in a variety of products from paints to dry chemicals, an insulation material as sawn and molded shapes as well as loose granular, a mild abrasive in polishes, and a silica additive in cement and various other compounds."

If this is the same stuff, the fact that it is "chalk-like, soft, friable, earthy..." and "very low in density (floating on water at least until saturated)" would make me hesitate before using it as a substrate in a planted tank.


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## egementt (Jun 27, 2006)

Yes its what I'm talking about. But it isnt floating on water. It looks like chalk but doesn't have a effect on ph. It isnt very soft I mean if you try hard you can crumble it with your fingers but this doesnt happen on its own. so since its used in filtration I tought to myself why can't it be used as a substrate.


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