15 inches high with flourescent or t5's? thats awfully high. I keep my T5's about 4-5 inches over my tank. Id say the T5s anyday over any CF's no matter the wattage almost...
T-5s are the best bang for the buck.Their no where near as expensive as halides,dont produce the that haildes do,and you only have to replace bulbs every 12 to 18 months.