That sounds about right. Dr. Ron advocates over 4” for a deep sand bed. That is my preference. The live sand can contain bristle worms in addition to brittle stars etc… Toss in a couple of Nacessarius (Sp?) snails as long as you remember that they will need food as well. They will surface when you feed your tank and do a “clean up” of the refuge without harming or consuming thelife you are trying to culture. One of the major questions might be what are you keeping? For softies the bacteria and the critters can definitely help. I have no experience keeping SPS with a DSB and have never researched it. I do not know what the benefits or drawbacks might be if that is the route you are taking. I am going from memory, but I seem to recall the idea of anaerobic zones in a DSB being a benefit- though there are some who will tell you that it can lead to a collapse in the tank. I disagree and have a huge amount of sand “in waiting” for a dsb once the refugium arrives.

One last note- it appears that the sand particle size is the major concern when planning a dsb- and it is fairly small (you may have to look it up as I just do not recall anymore…)

IMO if you want to keep LR and chaeto in your fuge, then don't try to keep a DSB ( or regular ) in there. it makes it almost impossible to properly maintain the sandbed and nasty things will start happening. what is good for the sandbed is bad for the fuge and vice-versa, if possible it's best to keep these two separate.

when i moved my system ( 3 - 4 years ago ), i added a sandbed to my fuge because i only put about 1" of sand in my display. it worked ok because i had easy access to make sure the sand wasn't getting clogged with detritus. about a year ago i moved some LR into the fuge, making it a big pain in the butt to keep clean, or even see what was going on down there.

a while ago i decided to clean out the fuge, here are a few thumbs that show the fuge before, the water after removing all the sand and rinsing the LR and how it looks now. there is a tonne of life crawling all over the LR and living in the chaeto, so i don't think i lost that much life and i have sand in other parts of my system, so those dwellers have a place too.


http://i200.photobucket.com/albums/a...mp20081212.jpghttp://i200.photobucket.com/albums/a.../th_sponge.jpghttp://i200.photobucket.com/albums/a..._fugefeb11.jpg