I posted this question in another forum, but I thought I try asking here. I noticed that my fixer (Agfa Universal Fixer) turns pink after a few printing sessions. When I checked the ingredients on the label, they are Ammonium Thiosulfate and Sodium Sulfite. From what I've read, both are neutral to slightly alkaline when aqueous. The Material Safety Date Sheet states that the PH is about 7.6 - neutral to slightly alkaline. I figured the pink colour is due to the Indicator Stop Bath being neutralized by the alkaline fixer. But doesn't that also mean that the stop bath is acidifying the fixer? I thought fixers like TF-3 and TF-4 where the only ones that were supposed to be alkaline. So, given that one of the reasons to use an acid stop bath (when using an acid fixer) is to neutralize any carried-over alkaline developer, is it a good idea to use an acid stop bath, like Kodak's, given that this fixer is alkaline? Anyone know?