thanks for your comments. I currently have a wooden cannopy which I had built for my 65 gallon and I just took the front piece off. So, I could conceivabley use a retrofit, though I don't think it will save very much. I am reluctant to use the metal halides because my tank is already running on the hot end and I think I would t hen need a chiller. I dojn't know much at all re. corals so I am fine at this point just going with the hardiest. My current tank inhabitants are a yellow tang, a gobie (forgot the name - long, thin, blue with orange - 3"), domino damsel, fiji damsel, 3 peculas, French Angel (does this rule out all corals?), and a small gobie or wrasse (1 1/2") - never have been able to identify it), and two urchins. Are there particular corals which would work/not work with these inhabitants? Where does one look for used lighting supplies? In the past I have just upgraded by buying whole but incomplete systems leaving me with a whole lot of extra stuff i don't need thought still more affordable that buying new.