Fine stuff found in the bottom of filters is common as NO media filter can remove the really fine stuff.
Folks that want to avoid all these problems have other choices.
Cheap is a gravity day tank, with a sump. THAT IS MAINTAINED
Better , esp for the few offshore folks is a centrifugal unit like the new small Alfa Lafal that does a better job than media style units.
Most of A-L items are for the commercials , but they do offer items for the white boat folks.
Oil treatment – fuel oil and lube oil separators ... - Alfa Laval
www.alfalaval.com/industries/marine/oil.../Oil-treatment.aspxAlfa Laval
Whether maximizing the energy you get out of your
fuel or extending the lifetime of your lubricant, our oil treatment ... Filtration - Automatic full-flow
filters, CCU.