[beeje]

The tanks are of a 2 piece design with the top glued on to the bottom half.
There have been numerous reports of failed/leaking tanks.
It is my belief that over filling these tanks causes them to split open at the glued seams.
NEVER let them get that full before dumping.
NEVER travel with more than a few gallons of waste in them. The sloshing around could also rupture them.
A better option for you could be to connect to a portable blue tank and leave the gray tank valves open and dump it when its full. You will have to check it often so you don't over fill it.