I had a similar problem with my new Montana High Country 5er. There was a slight smell, seemed like, all the time. I used so much Dawn and soaped up those 30 pound tanks and hoses and connections looking for leaks, they should stay clean for years now!
I always use one tank at a time, and the other is turned off completely. When one goes empty, I flip over to the other one, and turn the first one completely off. It made no difference which one was on and the other off.
Well,.... after many many fill-ups (because we used the trailer over last winter), I realized one day I didn't smell "it" any more. I did not do anything different, except give everything a super-duper bath. And to this day, there is still no more propane smell. I don't know what happened different. But I'm glad the smell is gone.
