I now use mostly TF2 for paper. For film, since I tend to use staining developers - and wish to preserve the stain - I mix a little Ammonium Chloride in plain hypo. So it can't be stored overnight? So what? I mix only as much as I need for one round of processing, and buy my hypo in 25kg sacks. I see no reason to skimp on the fixer, nor for worrying about exhaustion...