[1retired06]

Unless you did an immaculate flush, storing the black tank dry will cause anything left in the tank to turn into concrete. We don't have the smell issue you have, we do flush all tanks via hose thru the toilet a couple of times and then we close up the rig. Our Montana seldom sits unused for more than three weeks. I will take a wild guess and say the major contributor to your odor issue is "stuff" in the tank still left after your flush. Difficult to get it all.