A lot has to do with how clean you get your tanks when dumping. If stuff is left in the tank from the previous time, the smell does get much worse. The next time you are someplace with full hookups, fill a 5 gal bucket with water from the shower and pour several into the toilet with the sewer valve open. On occasion, before leaving home, I will dump 5 gallons of water into the tank and 1/2 gallon of bleach. It is also a good idea to have water in the tank before you begin using it. Also, a grey tank can smell just as bad as the black tank.