[MaxwellD]

Problem was that the Grey and Black tank labels were backasswards. THe grey tank was in fact full but it was labeled as the black tank which I did not mess with. A few days ago I was flushing the “black tank” and was wondering why the return looked so clean - I just figured I was a real clean guy. Who would a thought that the tanks were mislabeled. Wow - working fine now - although I think I may have damaged the HEPA valve which is what I think I had in the shower drain. I guess I can live without that - seems to be p-traps under sink and under RV main drain so not sure it is needed anyway. I appreciate everyone’s help and concern.