How do you long termers handle grey & black water?

We Cant Wait wrote:
Both closed unless you want to take the chance of ending up with a Grey Tank full of Sewer Flies!!!!

This is a good enough reason!
We keep all three closed. :B

We have a Black, Galley, and Grey. Then about once every four days or so I dump them all. Black first, followed by the Galley, then the Grey to flush it all out. god for another four days or so.