I got tired of weighing out the ingredients for fixer. It was tedious, and I often wasn't real careful about it. Fortunately, fixer ingrediant proportions aren't really all that critical. In any case, I decided to try a volumetric approach. It works well enough, and it's a lot easier. This fixer is based on Kodak F-34, but the proportions are not quite the same. The pH measures 6.5 at 18C. If you want to raise it a little, increase the sodium sulfite to 1-1/2 tsp. (teaspoons).
I like to premeasure the dry ingrediants and store them in old 35mm film cannisters until I need to mix up some fixer. Then I add the premeasured contents to the ammonium thiosulfate solution. A film cannister will hold enough for 2 liters of fixer.
Ammonium thiosulfate (60%) 3/4 cup (200 ml)
Water to make 33 fl. oz (1 l)
Sodium metabisulfite 1 tsp (12.6 g)
Sodium sulfite (anh) 1 tsp (8.8 g)