[Gil]

Do you all use biocides for a reason? I know when I was a boater my boat would always have biocide treatment. Of course, the marine environment is so much worse than the environment our RVs are subjected to. Large boat tanks are subjected to far greater temperature swings and the tank vent rest not far from water adding to the likelihood of humidity adding to the problems. Even most marina fuel tanks are subjected to far more harsh environments given so many are still exposed above ground tanks.

In the thousands of miles I've driven my coach I have never pulled a Racor primary filter black with the crap biocides are designed to prevent. My coach does sit for months and I'm not one that keeps my tank full, like I was as a boater. Having done the Alaska trip I would imagine some of the stations I had to use probably don't have the best of fuels. Still, nothing visible in the Racors. I don't know if you are using steel tanks, I know my Prevost tank is some poly material. Maybe, that makes a difference.