Had this trailer for 8 years. Had to replace the water valve a couple times, but never had any problem with any kind of smell : Until now. seems like even after draining the black tank, closing the drain valve outside, treating the tank, it seems to be smelling a little bit. Nothing to panic about, as it does not seem to smell up the entire trailer, just in bathroom area, however, wifey, wants it fixed. Plan on using a wand to perhaps dislodge some stay behind in the tank and see if that helps. Not sure about any seals around the toilet and the floor, like in a house with the wax seal, etc. When I ordered the flush mechanism they also sent a large rubber seal with the mechanism, but I did not use it, but still have it. Any ideas as to whether I should try to install that seal (if you know what I am talking about)? Other ideas? tkis