[Mikendebbie]

krobb - I have similar unit (2018 model). My rear black tank flushes like a champ, but I have to work longer on the front bath black tank. The reason is in how the tanks sit in the frame. If you look at the screen shot below - the rear/half bath black tank sits in the higher section of the frame (B). The front bath tank is located in the lower section (A)...so, the half bath tank has the advantage of higher elevation to help it flush and rinse it out. The front bath tank takes more time and “fill then flush” cycles for me.