a refugium does not take away the need for a skimmer. a refugium is a good place for pods to grow and reproduce away from the main tank, so they won't be eaten as fast. it's also a good place to grow macroalgae which can benefit by using up the nutrients that are needed for undesirable algae.
a skimmer actually removes bad stuff from the water. as uneaten food desolves, feces and urine floats around, algae, etc etc, it can be left in the water and contaminate the system if not for a skimmer. these bad particles attach themselves to the tiny bubbles in the skimmer and are "skimmed" out of the system via the foam in the skimmer chamber that escapes into the collection cup.
so in these ways, a fuge and a skimmer are very different things. a fuge can be very beneficial, but a skimmer is pretty much a necessity imo.
as far as the lights on the tank and fuge, I've read that the lights on the fuge should be on a reverse cycle from the main tank's lights. what I take this to mean is that the fuge lights should be running when the tank lights are off. Not positive on this though since I don't really have a fuge at the moment.
