Steve Dooley wrote
Can I put a bladder inside the extra water tank so it is
easy to
convert between diesel and water storage?


Scotty wrote:
no need to. Water and diesel don't mix. Water is heavier
than diesel. Just run your water lines off the bottom of
the tank and your fuel lines from the top.


That's right, the Navy does it exactly like that.

I'm not kidding, google up "compensated fuel/ballast tanks" although
most of the hits will be in regard to ecologic impact of discharging
ballast water from said tanks, you should be able to find something on
the fuel side.

signed- Eayyam A. Injun Ear (formerly known as Eagle Eye)