1) One has to get rid of potassium salts, if there are any in the developer. Rodinal is a good example of potassium-containing developer. The reason is that potassium thiosulphate is inactive as fixer. If potassium salts are carried over into the fixer, it will exhaust and fail to work a lot sooner.
Originally Posted by Noble
2) Yes, getting film onto reel can sometimes be tricky. I do not struggle with Ilford, Kodak or Fuji, but some of the others are a real PITA. Foma comes to mind. I'd sooner spool a strip of clingwrap. Maybe the newer Foma films have a better base. What reels do you use? I have no luck with the stainless steel reels, and have happily standardised on Paterson reels. Others swear by stainless reels. Whatever you use, the best in my opinion is to sacrifice a roll, maybe one for which development failed for some reason, and use that to practice with in daylight.