We have been traveling for the past 5 months and have been experiencing sewer/gray tank odor inside the motorhome. We have done everything we know to do, thoroughly cleaning the tanks, using a couple different types of chemicals, dumping ice into the black tank while driving. We believe this is a gray tank odor just because of where it seems to be coming from. We have a bath and a half, and the smell doesn't seem to come from the rv flush type toilet but does smell in the shower bath with a macerating toilet. We have a dishwasher and I do use it fairly often but clean dishes before I fill it. We have run out of ideas. Can you help?