In the current thread on alkaline stop baths, Photo Engineer made this comment: I use plain water in a Nova vertical slot processor instead of a traditional stop. It does have to be renewed frequently which wastes water, something I'd like to avoid. I'm considering an acid stop bath, perhaps acetic acid or perhaps Ryuji Suzuki's buffered acetic acid/acetate bath. I'd be tempted to use a more dilute version to minimize carry over of acid into the fixer (which is near neutral pH). An alternative stop bath that I've read about is a sodium (meta)bisulphite solution, which is acidic (and smells of SO2 but in a slot processor maybe not too bad). Would the bisulphite be an effective stop and developer-removing agent? Has anyone experience in such a stop bath?