I have dropped 2 tanks (97 f-250 7.3)(2001 f-350 7.3) over the last year due to failed fuel gauge senders, might be bio related. One tank (2008 f-350 6.4) to shorten drop tube. Tanks were clean as new tank. I first had bio made from linseed oil, then soybean oil, now it is chicken fat. I get all my fuel from a oil company that makes b-99,b-50,b-20, b-10,. All they sell is b-10, b-20 other(b-99,b-50) is for their use and mine, (b-99 is $4.00 )(b-50 $3.75 )(b-20 is $3.24) I changed to b-50 today, will change 3 to 4 weeks to b-20 for all winter! I have found filters are the main thing for running bio!