A simple solution to this problem is to design the tanks by putting the fuel P-U from a sump at the very bottom of the tank instead of running a tube from the top going down that stops just short of the bottom. That way nothing is allowed to accumulate at the bottom and any water or smutz thats in the fuel is immidiatly or continualy pulled out and through an external water seperator that can be easily serviced. I know Mac uses the tube going down from the top style and those guys have to watch things closer than those of us sucking directly off the bottom like Pete and K-W.

I'm no sientist but have been told that certian fuel additives actually allow you to burn the accumulated water in the tanks by attatching a few additional molocules to the water changing its structure and making it combustable.

As far as the bacteria issue? How about get out and use it more frequently