I recently set up a retro Icecap 5x39w T-5 fixture. I have a few computer fans set up along the length of the bulbs to blow air across them and cool them down. Now, from what I understand, if I cool them down too much, I can actually reduce their light output. It's a variable voltage, so I have control over how much air I'm blowing out. Does anyone know if it's too much to have all three 60mm fans going full speed, or should I throttle them down? Can I visibly tell if I'm cooling them down too much?