Quote Originally Posted by Erik Prestmo View Post
Filling the tank from emty dilutes everything 1:20 and after a very short time equilibrium between concentration in film and water is reached (this time gets slightly longer as the concentration sinks)
What makes you think it's a very short time? I haven't investigated this myself, but I recall reading someone's results in which they concluded that stand time in the rinse water was a highly important variable in the amount of residual hypo, precisely because it takes some time for that equilibrium to be reached.

I'd like for you to be right, however, as it means my film is better rinsed than I thought. :-)