[hankaye]

BamaRam, Howdy;

Interesting that you mention the "glug". Question, Do you have a see through
section so you can watch and see when the flow runs clear (for black tank), ?
I ask as I may have somewhat of the same thing happening with mine.
What I see is that the flow actually fills the 'slinky' and backs up until enough
has drained then I see the flow as "it should be" until it runs out. This may be
what is happening with your system. Only my observations and thoughts.

Hope it's that simple and nothing is 'wrong' with your system.

hank