For the brains trust. I have a brown viscous liquid that I drain out of my fuel filter from time to time. This sludge does not mix with the diesel or water. Diesel sits on top then the sludge and water underneath.
Any thoughts as to what this may be?
Scrubby
Not rust. Tanks are fibreglass. I do use fuel treatments and I did consider it may be a component of the treatment but I thought the treatment was supposed to be miscible in hydrocarbon.