I finally was able to locate someone that could answer my question of a special biodiesel fleet guard filter. It is fine up to biodiesel 20. It will handle that with no problem.
When I was an otr driver we used Pilot/flyingj quite a bit. You would think with all the talk about damaging engines they would be concerned. When I stopped for fuel I never looked to see what blend it was. I fueled where the company said to fuel. We changed our fuel filter every 15,000 miles, which was about every 4 weeks. Never noticed any difference in engine performance of mpg.