Just as Asaint suggested it would be helpful to know your water parameters via testing. Although here is where the main portion of your problem is
"72" Aqualight Pro: 4x96 Actinic, 3x150 HQI MH
, 4x1 moonlights"
Even though that is far less wattage per gallon then you would need for a successful reef it is no doubt going to grow some fine green algae. The good news is green algae is not a bad thing whatsoever. Your yellow tang no doubt would enjoy some to dine on, as well as a variety of reef critters.
I would not really recommend a UV
sterilozer for a reef tank. Mainly since algae growth in the reef tank is not only natural but in my opinion desirable. It can be a serious eye sore but in the end a mag float or any compatable scraper can take it off enough to make the aquarium still pleasing.
I am assuming with the light profile you are planning on making this tank a working reef ... I cant imagine someone putting halides over a fish only tank. In that case keeping your algae growth supressed by cleaning the glass, etc etc is likely the most healthy option of a reef. I would be concerned that a UV
sterilozer would harm positive macro algae growth as well as the impending corralline algae growth, both are very important to a successful reef tank.
A good protien skimmer will remove a good portion of the free floating algae, since a protien skimmer removed dissolved organics and algae fits that bill. I would suggest for you protien skimmer wise is one of Aqua C's in sump models (there is a good variety) or if you prefer the hang on back option run several CPR Bak Paks.
Another helpful addition to combating algae growth is a Lawnmower Blenny. These guys are hard wired to eat algae and they do non stop.