someone sent me this I'm not that bright.
"Ethanol becomes corrosive once it starts to oxidize. This will cause corrosive acid to form. Secondly algae growth formation is caused by water contamination.
Ethanol is already water soluble so if not addressed properly it could cause major issues with any metal in a vehicle's fuel system or fuel pumps."
And this
"Ethanol itself is not particularly corrosive. When the oil companies first started blending ethanol in fuel, it corroded some rubber and plastic gaskets on some cars and equipment. Manufacturers figured it out and substituted new materials. The unlucky consumers whose equipment was ruined or whose fuel systems had to be replaced just took it on the chin as per usual with most government programs.But that wasn’t the end of it.
Ethanol attracts water. When the two get together, they create the perfect environment to grow a type of bacteria called acetobacter. After getting drunk on their EPA-sponsored kegger in your gas tank, the acetobacter excrete acetic acid. And acetic acid is very corrosive.
If you’re refilling your gas tank every week or two, acetobacter don’t have time to grow a sufficient size colony to damage metal parts in your fuel system. But if your fuel sits for longer periods of time these microorganisms continue to multiply until your gas tank contains damaging levels of acetic acid."
No I don't really understand it either other than best advice is line fuel tanks.