Boy did you open a "Can of Worms". I don't know if this is the answer you want, but I read that VHO's are the best for actinic lighting. I was going to set up a new light rack with VHO's for supplementation, but T5's are becoming more and more popular. I read that the par from T5's has a big deal to do with the reflectors and cooling the bulb. Check out this link and you will see a ton of T5 discussions.

http://reefcentral.com/forums/forumd...s=&forumid=212

-David