I'd love to know what Kelvin rating of bulbs are you using and how many are on at a time? I have a trio of 39watt T5 HO's over my 40b tank, too, but I'm concerned I don't have the proper bulbs in it. When I use more than one lamp on at a time, I get algae on the glass and the driftwood, though I know I don't have enough higher plants to out-compete the algae at the moment. I currently have one 6,500K and two 10,000K bulbs and they probably are not the best quality either from some comments I've read, they are the bulbs from Odyssea.
I absolutely love the look of your tank, great job!! I can't imagine what else you could do to this beautiful tank that would improve upon it, it looks perfect to me!