I tried to refix prints (didn't work) and the film (worked).
Fixer is a "Ornano" superfix. On the label times are within the range 1 to 3 minutes both for films and papers.
On a Italian photography site i found a forum where a subscriber said he usually fixes gis films with Ornano for 25 to 30 minutes.
Film was a Ilford HP5 400 iso
The best way to determine fixing time, is this:
Clip off a piece of film,it doesn't need to be very big, for 35mm a leader is sufficient, a cm square is big enough. Put a drop of fixer in the middle, let it sit for about 30 seconds or so, then drop the film into a small bowl of fixer, time it until the spot disappears completely. This is called your clear time. Double this
and round up to the next minute. If your worried about pink TMX/TMY then go 4 times and round up. You just don't want to go more then about 20 times. Put the clear time in the fixer working solution bottle.
So if your clear time is say 45 seconds, that means you should fix for 90 seconds so round that up to 2 minutes, anything between 2 minutes and 15 minutes is fine.
Each time you use the fixer, you repeat the test, when the time doubles, then toss it and mix fresh, so if it started at 45 seconds, and your old fixer takes more then 90 seconds, then it's time to mix a new batch. Mind you with fresh mixed, if they are saying 1-3 minutes fixing time, and your not clearing in 2 minutes, then you either mixed it wrong, or the concentrate is no good, try mixing another batch, if you get the same result, look at the concentrate, if there are bits floating in it, it's dead. I would be asking the dealer some hard questions if you had just bought it though.