Bleach is the most expensive component in C-41 chemicals. But theoretically it is never really exhausted. I dug out my collection of Creative Darkroom Techniques magazine and located an article written by Dr. Robert Chapman talking about reuse of C-41 bleach indefinitely. Yes, you read it correctly. It is reuse C-41 bleach indefinitely. The article said by introducing a brief wash between color development and bleach it is possible to prevent most of the carry over of the developer into the bleach. As a result with proper aeration to restore oxygen and occasional PH adjustment the bleach can be reused indefinitely. Dr. Chapman claimed to have reused his 1 liter bleach for over a year. I understand bleach is critical to the result of C-41 process. I often got grainy negatives becuase of bad bleach. My question is is this realistic? I have a PH meter with a working probe. I have discovered an economical way of calibrating it and keep it calibrated. It is really tempting to give it a try. It can be very easy by using a JOBO processor adding a 10 second wash between color development and bleach. I probably want to reduce color development by 5 seconds or so. What do you experts say about this idea? If it works for a year I will be more than happy to dump it. It also puts my PH meter to use.