Upgrading

[rbaby]

I finally decided I've had enough with the Eclipse system for my nano and decided to get a Nano Cube.
Any thoughts on this? I saw a Nano Cube Deluxe which...with its stock lights are 48 watts of lighting. I believe they are 50/50 lighting--what kind of corals can I safely keep in this? In my Eclipse tank I currently only have like 13W of lighting, and I have some zoos and a mushroom, which I target-feed with some liquid plankton once a week...they're doing okay but I'm sure they're not growing to their full potential which made me want to change my tank.
Does anybody have this type of tank and if so, how has it been working out for you? I plan on getting the 12G Deluxe one...what other gadgets should I get to help ensure my tank's happiness?
I don't plan on getting any more fish, I have 1 clownfish and 1 orange-striped goby, they get along and my bio load has been stable even in my 10 gallon...so I don't plan on adding any more fish--but I do plan on adding more corals...with my current bio load as I've mentioned with the fish and current corals that I have, is there a limit as to how many more zoos, and/or mushrooms I can add? I'm not familiar how much of a bio load those will add to my tank. Any help would be great, thank you.

 

[rbaby]

Also, I read that the Nano Cube has 3 filtration systems, one that has the bio balls in it--and from what others have advised, I was told that it was really bad because they become nitrate factories.
Is there any way I can convert that li'l area into a mini sump where I can hide my thermometer and heater etc.? I don't know how the bio-filter works, if that li'l compartment fills with water up all the way or not, if it does not, how can I get it so that it completely fills up with water? Thank you.
I forgot to add--any corals under my to-be lighting setup that I can keep that my clown can host in? Right now, he likes to host next to a powerhead...which is kinda strange, but hey, it keeps him company. Don't have enough lights for an anemone but want to get him a coral he can snuggle up on and eventually host in that my tank can support.

 

[upinsmoke]

it keeps a little lower than water level but for the most part it stays full.