Good Evening's All - Much appreciate (incremental) remedies.

Comfit is a Carver 520 with 2*400 gal. tanks. There are two vents on the
sides (2 per each) that will vent diesel after filling 10 gal. into 200
gal void.

I just spent 1.5 hours putting 200 gal. into each of two 400 gal. tanks. We
had to put a cloth over the two vents to stop diesel going into the water.

Do you have any suggestions on how I could fix this?

Dave