Here's another idea, perhaps much easier to implement for short lenghts of film than the PVC drain pipe processing tank I previously posted. This is from Popular Mechanics, October 1947. This article was written with movie film processing in mind, but you can adapt it easily. You'll be doing tray processing, but the methods described are simple to implement.

http://books.google.com/books?id=0N4...page&q&f=false