We added (10) Cree XP-G, XT-E and Osram LEDs to our T5 light. We mounted them on a 1"x.1"x36" aluminum bar and attached the whole strip to the underside of our Current light. We are driving them at 700mA for a total power consumption of 23 watts (3.2V x .7A=2.2w each). The LEDs add great color and shimmer to the aquarium. You can find more information here
http://azarmi.com/reef/profile.html