Fuel Contamination and Your Tank
Many belly/base tanks have structural walls (baffles) inside the tank, typically installed to support the engine weight above it. These baffles inhibit proper fuel flow and obstruct complete tank access. If a belly/base and a cylindrical tank hold the same amount of fuel, and a certain amount of water is added to the fuel, there will be a significant difference in the fuel/water interface surface area near the bottom of the tanks. Microbes live in the water, but feed on the fuel, making rectangular tanks much more susceptible to bio-deterioration and localized water pockets.