Hi Atlantic,
I have a 20 gallon reef with 55 watts of PC and 1 blue atinic strip. It has been up and running for close to a year. To give you some idea's, in my tank I have:
Sea Pen, Leather finger coral, Toadstool coral, 4 kinds of mushrooms, star poyps, green button polyps, Frogspawn, Pinapple Coral, Chili sponge. I also have a LTA that I added 3-4 months ago that is getting kinda large.(sure is fun to have with clownfish though) My tank is very full with these. They are all thriving well in my tank, I do monitor it very closely though. I also have 5 fish.
P. S. I put on a Red Sea Prism skimmer a few months ago and what a difference in the water quality, basically took care of any excess algae problems too.
Hope this is helpful, happy reefin!
Toni