So, I'm still getting to know my 310-GK. Today it dawned on me that I have two black tank monitors...which tells me that I have 2 black water tanks...but one drain valve and only one bathroom.

How exactly does this work. I've seen a bunch of posts but no answers to the question.

After a week one is 2/3 full and the other empty. Does one spill into the other? Obviously the one gate valves drains both...but does the tank rinser clean both tanks?

It makes no sense to me.