My gen shed uses a "day tank" of 15 gallons capacity with sight glass. The bottom of the tank is an inverted pyramid with babcock valve drain. From there it goes into a LuberFiner C-750L filter which is normally used for bypass lube oil filtration. It filters to 10-microns. From there it continues to gravitate to a RAcor fuel water separator with s-series 1-micron element. I have a "T" tap there for fueling the lomborgini air cooled diesel DC generator. The day tank is maintained 100% re-filled after every use. The LuberFiner catches most of the crud while the settling tank dierts a vast majority of condensation and contamination. Getting a pump properly rebuilt down here is almost impossible.