i agree with one of the other statements "if it ain't broken" don't fix. I have been using Xtol 1 :3 with my students off and on for sometime (depends on film type). No problems, however, i do use a magnetic stirrer for mixing all chemicals and I have been thinking perhaps that may help reduce problems. Also, we also mix one liter of solution, even if only one roll of film is being processed.(posted 8438 days ago)