For my 375 I started out with a bathroom fan in the fish room, and found that it was noisier than I liked given its capacity, and salt creep became a problem.
Eventually went with a Vortex inline squirrel cage fan like the attached.
http://http://cgi.ebay.com/ws/eBayIS...tem=7721464970
Much quieter (also due to being placed remotely in the finished basement ceiling) and more powerful. Vented out the wall, with a fresh air supply provided to avoid any negative pressure situations.
I got mine from the local hydroponics store ... they even accepted a charge card
