I have bulk tanks diesel and gas tanks at both farms. Bought used but nice at farm auctions, I inspected the interiors, flushed them out (about 10 gallons diesel for the diesel, same for the gas), blasted and then painted the exteriors with POR-15. I top coated with Rustoleum. You should run both a fuel filter and a water separating filter inline, and change at least annually, depending on how much you flow.
Leave the Stabil for the guys storing little cans and winterizing their lawnmowers, weedeaters, and chainsaws. It's a consumer-based product and isn't any good for bulk storage, especially if you're talking for a year or more. (Gold Eagle does however make a great engine fogger).
Use Pri-G for the gas, Pri-D for the diesel tanks. One quart treats over 500 gallons. It runs about $30/qt. and is available many places online.
I buy only non-ethanol gas for the gas tank from my farm Co-op. Runs about the same as mid-grade, including delivery cost.
