I ran out of TF-4 the other day so I mixed up a batch of sodium thiosulfate with ammonium chloride to speed up the fixing process. The fixer worked well on paper and I would like to use the same fixer for film. Most recipes that I have found for sodium thiosulfate fixers have 15 grams per liter of sodium sulfite. The few ammonium thiosulfate seem to have lower levels of sulfite. Should I lower the level the sulfite level so that I don't weaken the staining action of the PMK?