IMO it's not enough room for a sandbed to be worth it. Shimek used to recommend 8" on 4'x2' as the minimum. There is some pretty good filter media options out there if you wanna look that way, and/or just stock it lightly.
What your describing with the screen layer sounds more like a Plenum. I just threw away Goemans books on Plenum. I looked into them as well (why I bought the book) but following up with other reefers, none of them kept it for long.
JME
Sent from my iPhone using Tapatalk