buy the largest they make any HOB will work you may have to MOD a bit more but there are some that are nice and long that would work realy well. I can't remember the make they have two over flows you would have to block one they are also black, you have to remove the lid anyway; but the volume would be more than the AC. they are very easy to convert I'll lock for the thread and post.

Found the thread.

http://www.canreef.com/vbulletin/sho...t=DIY+refugium


Bill