On the rock, my choices are 90% dry rock and one super Live rock from your lfs to seed the dry rock. It takes a bit longer for the other rock to come back to life but it also forces you to slow down. On sand, IMHO, stay away from the very fine sugar sand it blows around your tank all the time. I ran a skimmer (Tunze 9002) on my BC29 but 20% weekly water changes will work just as well. I guess the big thing to remember is things go bad a LOT faster in the smaller tanks and it's very hard to recover. IMHO the smaller the tank the more time you have to dedicate to it. You'll get lots of help on RS, just ask, other will jump in. Good luck!