Substrate in Refugium?

What type of substrate should i put in my refugium? Sand, mud, Kitty Litter?
and how deep should it be? I will also be growing cheato and some macro algae in the fuge.

 

Here is a good article on DSBs. Mud is really just sand with clay content. Some folks here use kitty litter. I don't really see the need for super expensive magic potion muds. To each their own I suppose.

 

thanks powerman

 

I went the kitty litter route, approximate 4" to create the effect of a DSB. I have not had or observed any issues with this set-up.

 

It would help if I actually posted the article.

How Sandbeds REALLY Work by Ronald L. Shimek, Ph.D. - Reefkeeping.com