Hey TF. I just picked up a decent light fixture. Its a 2" 4 bulb T5HO fixture. As you might know, and I have been told, and just learned in a huge way, these lights run MUCH hotter than T8 bulbs. The surface of a bulb is reading about 150F. This brought my tank to almost 100F within an hour. My strategy so far has been to turn the tank on its side, which is keeping the air temperature around 80F. I feel I'm losing some significant light this way. I remember reading that glass blocks almost 100% of UV light. This seems to be true, because plants that were almost burgundy are now turning light pink, or even green. I'm thinking I may use an open-air grow shelf, coupled with reflective surfaces and a computer fan to bring the lights as close as possible without cooking everything.
How do you manage heat in your set ups?