I'm always reading about fuel line degradation. I am not understanding why boat fuel lines degrade so fast. When I put the same fuel in my truck and cars as I do in my boat why is it that I dont have problems with my vehicle fuel lines degrading yet on the boat it is an issue? If it is sun and salt exposure than is it ok to use auto grade below the deck and marine grade above the deck? The guy at west marine told me their fuel line was not very good. Then why the heck are they selling it?