What size PC/CF bulbs do you need? The most commonly recommended one for say a 24" 65W bulb is the GE 9325K bulb that goes for ~$10 at Lowes.
T5's are about 1.75 times as efficient as NO (normal output) bulbs, which the "1 watt per gallon" rule was based. PC/CF bulbs are about 1.35 times as efficient as NO bulbs. With that in mind, you would need approximately 75% of the wattage of a PC/CF bulb in a T5 bulb to be as efficient as a PC/CF bulb. So for example, instead of having a 48" 130W PC/CF fixture you could get the same results (or better since T5's have better depth penetration into the water) out of a 48" 100W T5 striplight.