hey im new to this rv and loving it, we just got back from our second long weekend and everything went great, when we got home after about a 4 hour ride we went to clean out the rv and noticed a sewer smell, dumped at the campground and everything was clean, wash out and put chemicals in tank and added about 10 gallons of water for the ride home, any suggestions would be great,,,, ps havent had this problem the first trip. first time this happened, thanks