first of all, welcome to reeffrontiers!!
i would definately say that you need a skimmer, imo it's the most important part of filtering a saltwater aquarium. along with using r/o purified water and carbon. a good rule of thumb when buying skimmers is to get as big of a skimmer as you can afford and have room for.
back in the day i used to do reefs with just refugiums, but i never had the positive results or stability that i currently experience with using a large skimmer in my filtration. i was always having problems keeping the system clean, and despite the results i was suppose to have with the refugium, there was typically always an algae problem of some sorts. dont get me wrong i like refugiums, but just not as the singular type of filtration for a reef system.
and what ever you do, dont use ecosystem's miracle mud in your refugium, just use fine aragonite sand, or better yet, a few inches of assorted size range of live rock rubble.
some skimmers that would be good for that size system would be;
a.s.m. model g-2 or g-3
aqua c model ev120 or ev180
precision marine model bullet 1
E.T.S.S. deluxe reef devil (buy without pump, so you can upgrade)
hope some of this helps and good luck!