Converting Black Tank into a Grey Tank Overflow?

[al perna]

we have been living full time for 3 plus years . we spend approximately 8 days dry camping 9 times a year . what I find is as long as both tanks can handle all water on board, there has never been a reason for us to need the excess area of the black tank for water . You see , if I can get fresh water, I can dump grey water . In the rare cases where we have needed to dump and add water , there is always a campground around
I will also add ,8 days without fresh water or dumping ability, is long enough for us . When we attend Q , there is nothing wrong with driving 1 mile for fresh water and dumping every 5 days or so ..