You can see above that there is not a huge difference, except the colors have deepended a little, so T5's are a great alternative to using MH with lower heat. It cost me $125 to make the canopy with 2 4.5" fans blowing inside the canopy, $400 for my lighting which included my choice of bulbs. It would not have saved me anything to go with T5's which another reason for using T5's, so I just decided to go with MH. I do get a 2 degree swing in my tanks temp from 81 at night to 83 during the day, which means I do not need a chiller thank goodness. The was a big worry for me, was that I may have needed a chiller, or another small fan to blow across the back inside the canopy.