Why you should not leave your grey valve open - Sewer Rats

The only time I've had my bathroom stick when I flush the toilet with the vent fan on, is when I had it connected to the dump station with valves open. These days, my black tank stays closed until it is 3/4 full, then dump it. Just to keep stuff from piling up (literally), I squirt some Dawn dish soap in the tank after emptying.