You guys are fixing for 10 minutes? That's a long time for RC paper, even with regular sodium thiosulfate fixers. That 10 minutes is usually more than sufficient for films which take longer to fix out than papers. Ammonium thiosulfate (aka rapid) fixers work much faster than sodium thiosulfate based ones and will clear the notoriously difficult to fix Kodak's Tmax films in 2 to 3 minutes, with complete fixing accomplished in 7 minutes or so. Foma films fix out very quickly, and rapid fixers will clear an undeveloped film chip in a minute or so.
I thought we were talking paper?
We fix our films (Arista.EDU also Foma) in fixer for 5 minutes, I always fix my film at home for 8 though.