How about a big Racor or Dahl filter with a 40 micron element that can handle 6 or so gpm? Or do you need something much more coarse, like a big water filter? We have used all three preparing fuel for the Atlas, but generally use the Dahl or Racor even though the elements are more expensive. We have found that is never good to take all from a tank when we scrounge fuel because of the NASTY bottoms of dubious origin, and that gravity is your friend and settling takes care of a lot of ills. The fuel system for the Atlas is arranged to circulate through a couple of filters at 6-10 gpm continously to polish to 10 microns into a day tank then that overflows into the main tank. I don't know the specifics of your arrangement but fuel is where and what you find and getting it clean enough to run is important.
George