It's a very common problem known to newborn darkroom people :-)
I had the same problems once and APUG (as usual) solved my problem.
So, after one roll of film your fixer was dead.
Originally Posted by timpppa
How could that be? Have you examined the
problem and found an answer? Dan
Originally Posted by dancqu
No, the fixer wasn't dead, but I got mixed up with the fixer bottles and
used more diluted one which was used with paper... My mistake, but
nevertheless now I know if something like that happens again.