Substrate that doesn't cloud the water?

[Rikko]

The degree of substrate "kick up" depends also on the age of the tank (more than a few months and all particles will be heavier due to bacterial colonization) and your water flow. I've got a heavy flow tank so any time some sand gets kicked up, it generally does a pretty big circuit before falling to rest somewhere. I suppose you could try throwing a layer of crushed coral on top opf your sand bed, but there are obvious drawbacks. First, as sand dwelling critters roam around it will start to mix and bring sand to the surface again to restart the problem, and I've also heard that you can get stratification of the sand bed which for reasons unknown to me are bad.