Those bends are greatly reducing the airflow. I can't tell completely, but at one point it looks like the flex duct is corkscrewed. :stoned:

The path of least resistance is a straight line. Try to get it as close to that as possible. :thumbsup:

Also, never underestimate (as I did) the radiant heat that your fan will produce. It is designed to cool areas, but the motor will throw off some toasty-ness that could raise temps.

Hope that helped. :thumbsup:

This has tasty bits of info too:
http://boards.cannabis.com/indoor-gr...-progress.html