I'm using film hangers in small tanks (Cesco tanks) to proccess T-Max film with RS dev.. I can develop up to six sheets of 4x5 at a time. My question is, when it comes to the chemistry, I think I'd prefer to dump the dev. after each use, b ut with the stop bath and fixer, I think it would be a waste and would like to u se it for as long as possible, but how do I know when its time to start fresh? These tanks do have floating lids. I will be mixing part A and B of the RS dev. together and then when I proccess I will mix one part dev. with nine parts water as I have read to do it this way on this site, then to the aquired water temp. and time. I would appreciate any opinions from those who replenish the dev. inst ead of tossing it after each use. Thanks for the advise.