This subject has been addressed twice this year, but buried in otherwise titled posts. My purpose is to make a appropriately titled post for future gurus who could use the search engine to find the information. 

Here is a schematic of how the two valves are plumbed to the waste tank. 
[attachment=7833]

The first thing to understand is that the grey water does not flow directly into the top of the waste tank. All grey water is plumbed into separate lines that eventually connect and flow in