If your fish load is in the lower range, you would do great with just the live rock, and your skimmer. The skimmer will airate the heck out of your tank, and that will help your fish, and the bacteria on the rocks. If you have room though, I would just leave the HOB for now. You dont have to have a refug, it is just a plus. Same as a sump. I dont have a sump on my nano and it is full of corals!! Just worry about the ick thing for now, , and cross the other roads when you get there. This hobbie can be a cheap or expensive as you want it to be. My nano is basicly a FW setup with a power head for more flow.