A friend has a large sailboat that has a diesel engine installed for auxiliary power when needed. Since the tank is always exposed to moisture, there must be a way to remove that moisture periodically. He built a portable "fuel polisher" to clean and remove the moisture. I just searched a "fuel polisher" and found that on a boating forum, a user posted how he made one for his boat. I have used his polisher a few times to clean my fuel tank on the BX23S. If I felt that I needed to own one, I would spend the $300 that this would cost to build. Here is a link to the discussion and links to the parts used to build one. https://www.trawlerforum.com/threads/my-take-on-diy-fuel-polishing-system-15-gal-per-min.66931/