So I have been curius about this concept ever since I read the 450 gall L shaped tank thread here on R2R. If anyone who is in the know about this could explain it in more depth that would be cool. I thought a thread would help me and possible other fellow reefy types out there understand more about this. The guy was saying he was going to do an 8"sand bed in his refugium. I am just wondering what the benifits are and the particulars on what to do exactly?