Strad,
You're using fiber based paper? That does require 5-10 minutes, as does film according to my packages. But for RC paper, it's 2-4 minutes in the fix for both the Kodak and Kentmere powder fixer I use. I use the double bath and do about 90 seconds in each, 3 minutes total. I allow 30 seconds in the first tray of fix and then turn the lights on, and I've read as little as 10 seconds is fine for RC paper.