A reef tank, actually, is not terribly much like a fish only tank, except that the water is salty in both, IMO.
YOu monitor, and are concerned with, a few more parameters (nitrates become critical, as do things like alkalinity and calcium). Specific gravity in fish only tanks is commonly 1.021, which is highly stressful if not fatal to invertebrates.
Lighting is also critical, and stock flourescents will not be good for keeping much...so I hope you do not have normal out put flourescent lights
You tend to have far fewer fish in a reef system than in a fish only system.