Companies like Kodak and Ilford and independant groups have published values for the recommended capacity of their fixers. I leave the testing to them.May I, however, politely ask you, as a chemist, if you have a justification for this otherwise very sensible suggestion,
Once again testing has shown that in terms of residual silver a two bath system is better and more economical than a single bath one. I remember an article some years ago in either Modern or Popular Photography which showed this to be true.would you say that a two-bath fixer regime offered significant advantages to a regime that used only 1 fixer
A hypo clearing agent is important only if one is concerned with reducing wash times and water usage. Without one the amount of silver and thiosulfate can still be reduced to a desirable level but at the cost of time and water. The fiixing process is a diffusion controlled process. So the role of sulfite is to cause the paper fibers to release the silver-thiosulfate complex more readily.