The fan is in the 6" vent hole on the top, about 18" from the light. Hard to tell with the ducting. It is sucking air through the cool tube and exhausting it outside of the tent. I can't put it directly on the tube if that's what you meant. There is no room because that tube is frickin' long.
The temp has been at 78°F without cracking the window.

Big Bang-1 is giving me problems. The other two are fine, but this one is growing soooooo slow. She is 3.5 weeks old. It's yellowing bottom up, starting at the tip of the leaves. No brown crunchies or anything. I gave her the iguana juice when I noticed this, and I've been watching it get worse. :sadcrying