noteven wrote:
I have heard of an instance where the round piece of tank wall that was cut out for the valve with a circle saw got left in the tank.
I can attest that this DOES happen. About 3 years after buying my first RV (a Winnebago) in 2007, I was dumping at home using a FloJet macerator. I had a clear section so I could see when "stuff" stopped being rinsed out. Lo and behold, the circle of plastic that had been cut out of the black tank to attach the toilet dropped into the clear plastic connector.
My black tank drained much better after that.