We have just bought a 2 yr. old 5th wheel. There was quite an odor in the bathroom & the rv maint.told us it was because the former owners hadn't used control chemicals as regularly as they should...if at all. After reading everything thing I can on various threads, I saw where the odor can be coming up if the seal isn't as tight at it should be. Last night I filled the stool with water and sure enough, this morn., the bowl was empty. Now, to my current problem...how do I replace this seal or will I need to drive it back to where we bought it & have them fix it? Any advice will be much appreciated. We are new to anything above a pop-up, so I'm going to be surfing these sites regularly. I've learned alot just in the last couple of weeks from them! Thanks to you all of you who contribute the questions and answers!