I ran my fuel tank low and filled up with non-ethanol gas. Someone here on BBC said that it was bad to mix the non-ethanol with "regular" E-10 I had been running. WHY would that be bad. If I mixed an equal 50/50 (for example) of E-10 and non-ethanol, that would make it like "E-5". ANy harm? I did have my tank run low before ethanol-free fill-up