I think this is a topic where Colin can help out, but reading topics tonight has me wondering. I have an 8 pass radiator(which came from a walk-in bar cooler) with copper tubes, and aluminum fins. Various articles and posts refer to the problems of copper and aluminum not reacting together well. I contend that as copper fins run past aluminum fins that the chemical and thermal reaction does not occur, or does not at least to the detriment of a watercooling system. I would like to hear some opinion on this.