These things really suck as nano reefs...Sorry.
I had a eclipse 12 for a year and a half. I finally gave it up a couple of months ago. I turned the damb thing into a goldfish tank for the girlfriend.
The reasons:
lighting: totally weak 20 watt bulb! Need at least 3X this for a decent reef set up in a 12 gallon. I used a LOA pc retrofit into the hood though it was a major PITA to do.
filtration: filter pad and biowheel are bad news, plus the outflow of the pump constantly stirs the sand. This means that the intake will eventually grab some sand grains and fry itself trying to eat them.
Salt creep: think its bad on a regular reef? Try one with the water actually piped though the hood! I ruined a perfectly good entertainment center with all the salt that came off this thing.
Accessability: you have to empty the whole hood to get decent access into the tank. The flip up top is not big enough to do much of anything. Water invaribly mixes with electricity when you do this!!!
If you are still convinced its the way to go, I would do it without a sand bed, maybe 10-20 lbs of live rock on bare glass or starboard on the bottom. You could also use a UNTREATED cutting board from the dollar store, cut to fit.
Upgrade the lights somehow to at least powercompacts. Someone sells a plug and play upgrade kit however it is like 75.00 or so if you can find it.
It will be a major pita to clean as you go through your algae cycle but eventually, the bare bottom method may work where DSB failed miserably.
Sorry, hope my experience serves as a caveat to others. you are better off investing the extra 100 or so bucks to get a nano reef setup.