The trouble with smaller fuel company's is that sometimes in an effort to make a larger profit they will add cheaper solvents to there tanks.
this happened to me a few years back i had it tested in a lab at work and it showed up traces of Toluene and Methyl Ethyl Ketone(MEK) both ingredients in paint thinners worth 20 cents per litre.
The hoses ,rubbers,pumps have no chance Teflon is the only seal i know of that will stand up to them.