I currently have 2 20gal tanks, which are plumbed together, and are filled from a single deck fill. They are plumbed together at the bottom with a tee that goes to the pump. It has always worked fine, however, I would like to double the capacity by adding 2 more tanks in a similar fashion. The 2 current tanks share 1 vent that goes through the hull. The question is: Can I fill 4 tanks from the same deck fill, and utilize the single vent? I'm still trying to wrap my head around the plumbing arrangement for such a system. I have to go with 4 separate tanks because of access issues. They would be arranged with the 2 pairs ends facing each other, and then be plumbed together with tees for both the infill line and the vent line, as well as the line from the bottom of the tanks to the pump. Suggestions are appreciated.