Grey odor from washer/dryer area

[chickenman05]

Been trying to fix grey tank odor from washer area since purchase of 2016 Sunova 33c. Tried 360 vents, Geo method tank chemicals and dumping the holding tanks slow. Since M/H is sitting for another month I pulled the dryer out to access behind the washer. Think I finally found the problem-factory installed the washer drain hose too far down the drain pipe and into the trap. Splendide install calls for 6" max into the drain pipe to prevent siphoning. Winnebago had about 16" into the pipe and bottoming out in the trap. The trap was completely dry even though I winterized washer by running pink antifreeze though it. I'm pretty sure this was my problem all along so I installed correctly and changed out the cheap AAV vent while I had access to it with a good Studor AAV.