Well, bink, what I do is spill it out one box at a time, and go through every piece making a pile for every color, then I put each color in it's own box or drawer for later use. In all honesty, I can't even begin to empathize with you-I only have about one and a half of your tub's worth in bionicle pieces, so the sorting wasn't all that tricky, but you could still try it, I s'pose.
Oh, and thank you for showing us that adults can still have huge LEGO collections. It makes me feel not so... strange.(though, I am a little off in person)