How do you avoid Bio Diesel (over B5) while on the road?

We towed to Texas before arriving for our winters stay in Casa Grande. Pilot had B-5 but didn't notice at first so I only bought 15 gallons. Later at a FJ it was as the above post up to B-20. I filled this time because of the need. I paid attention to how the engine was running because of being a little scared.

I felt later it was purring like a kitten and felt better. Our 05 duramax was not made to run bio fuel.

chevman