Not sure if it's all that bad of a mixture, but if you're really concerned, use a turkey baster and suck out what's in the pump and put in the "F" fluid. After driving it for a bit, repeat and then repeat again a few more times until you have close to 100% "F" in there. Maybe I'm over-reacting, but better safe than sorry- you've already been through one rack...why chance it again.

Btw, I attached a round (the kind with a hole in it) magnet to the spring like underside of the power steering fluid reservoir cap with a plastic zip tie. When I change my oil I clean the magnet off as I check my fluid level. I always get a black residue from it...the fine metalic particles. Since we don't have a filter in that line I figure I'm "filtering" it to some degree. Might be worth the few cents it costs to add this to your pump cap as well.
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1998 S70 T5 Emarald Green Metallic (125K), 2004 V70 2.5T Ruby Red (45K), Previous Owner of Black '94 850 Turbo Wagon (Sold at 140K and miss her). My cars have been running so well lately they've got me worried.