There has been a fair amount of back and forth on this stuff on the web.
My guess is you are just as well to make a DSB with aragonite sand, I like the oolitic or sugar sized. And dose your water with iron. Iron is the key if you are growing macro-algae.
Here is a link on mud for you, if you scroll down you will see a post with lots of links to deep sand bed info:
http://www.reefsanctuary.com/forums/...send-scam.html