Cool Tube Info

I made a cooltube, seems to do pretty good, just wondering since I had a 6in inline duct fan converted down to 4 in on both sides will this hurt the air outtake. I have one end taped up, and the other end is pulling heat away going into a Y adapter with my other room exhaust that leads into the attic, just curious since the line coming from the cooltube gets hot for about a 18inches, then it cool, figured it would be warm with all the air coming from the light.

ok found the problem, had the end of the cooltube closed off, not a good idea. So with the two exhaust duck, the room and cooltube, and no air intake temps where in the 90's, now with no air intake, cooltube end open, and the Y adapter gone, thats right I have 2 exhaust ducts going to attic, temps are 83.8, I have a 8in inline duct fan on the way for air intake, hope the temps don't get to low.