I have a 10 nano. Do a 1 gal a week water change, and top it off everyother day or so. Keep the fish small and only 1 or 2. Then Load it up with corals. I have been keeping large green hairy mushrooms, finger leather, kenya tree thats fragged itself twice, and about four random mushrooms, under a 80W PC fixture. I don't even add any calcium or anything, just the water changes. Had all of these thriving with very little tending to tank too much. Not hard stuff at all really. Just keep up with the maintaince and dont slack on that and youll be cool. HTH
P.S. Use only RODI water, no tap. And a little DT's might help everynow and then with the corals.