Hello,

Thre are rapid fixers made by mixing hypo with ammonium chloride or sulphate (Kodak's F-7 and F-9).

It just happens that Kodak F-7 uses 50g of chloride, F-9 uses 60g of sulphate.

The molecular weight of chloride is 53.49g and of sulphate is 132,14g.

Doesn't it looks like there is too little sulphate in F-9?

Thanks,

Jorge