Sand depth...

[fishnet]

OK... I'm having a little bit of difficulty deciding whether to use a deep sand bed or a shallow sand bed and how deep either one really is. I've read where a lot of people have a 2" depth (SSB) and other folks have 6" depth (DSB)... so... what is 2.5-4" depth? I sorta put in too much sand (areas with 3, perhaps a little more) when I put mine in my 55 gal and I'm a little concerned that I may be creating a future headache.
Can I avoid having a true DSB by having critters that stir it like sand sifting stars? What other critters can I put in that will dig around in there? I have a goby that will probably enjoy it once everything settles down. (Amblyeleotris randalli Randall's Prawn Goby)
Any ideas or opinions?

 

[murph]

From what I have read its either under 2 inches or over 3. In between is no mans land. The best LFS in my town and the one I put the most faith in has very shallow sand beds in his display tanks that are as good as any tank I have seen containing wide varieties of corals and other assorted life that appear to be doing very well. His beds are probably not even and inch thick.
My 75g display tank has varying depths at the moment of almost down to the glass to as much as 4 and a half inches in some spots. I have no idea how good a thing this is but since moving my circulation deeper in the tank the sand has taken on a life of its own settling out in these shallow and deep spots.
I will have to move my tank before next summer and am leaning toward a shallow sand bed combined with a DSB only in the fuge.

 

[clownfish4]

I have a 46 gal and i only used a 2 inch sand bed. How big is your tank? I also have a blueleg hermit crab. I also have a emrald crab and he is doing fine.