There is nothing at all wrong with the Pot. Ferricyanide bleach for color work, other than it is environmentally noxious. Formulae for color include more refinements than those for black & white. C-22 was based on the Ferricyanide formula and C-41 replaces it with a more politically correct Fe-EDTA bleach that can be combined with fixer.

Your results will be improved if you look up and mix the C-22 bleach for use with your C-41 films. Also, note that pH for color processing sets the fixer to about 6.5, and usually includes some Sod. bisulfite to avoid degrading the color dyes.

M. T. Sandford