In furthering my general reading on photochemistry, I've recently stumbled across a puzzling contradiction between two sources concerning the composition of Rodinal, and I was wondering if anybody could cast any light on the matter. According to Jack's Photographic and Chemistry Site, Rodinal contains sodium metabisulfite and potassium hydroxide. According to Anchell's Darkroom Cookbook, though, Rodinal contains potassium metabisulfite and sodium hydroxide, and Anchell explicitly cautions against using sodium metabisulfite in place of the potassium metabisulfite. In doing further research, I've found other variants on these (mostly potassium metabisulfite and potassium hydroxide). Although I have no immediate need to know (I've got a bottle of Agfa Rodinal that'll likely last me a while), I'm curious about this discrepancy. Would both formulas work equivalently, and similarly to Agfa Rodinal, Calbe R09, etc., or is one seriously out of whack? Would these chemicals combine in solution to be equivalent?