The Sealand 510 is one of the best out there..
Sorry to disagree with Grey, but we hated ours with passion. We could not stand it after the first six months. We replaced the seal quite a few times, it would maybe hold water for a few weeks. Then we would just try to live with it until we finally got frustrated enough to replace it again. We replaced and rebuilt the foot valve, I don't know how many times. Dometic kept sending us new kits, and it went on and on. I couldn't stand the thing! If you get a 510, you have been warned. I will say I told you so later. However, we did replace it with the 310. I honestly had reservations about it, but we decided to give dometic another try. So far, we have about 8 months on it, and we haven't had any issues at all with it. There are NO serviceable parts on it. The seal goes bad, time for a new toilet. All tradeoffs. John
John, i was told that the seal was replaceable on the 310, was easy to do and was cheap. Gonna have to check into it a little closer and see if that is true or not.
Here is the toilet I have in my bus (the same as my house):http://www.lowes.com/pd_35099-20602-3386-0_0__?productId=1269839&Ntt=toilets&pl=1¤tURL=%3FNtt%3Dtoilets&facetInfo=this toilet gets poor reviews....[/font]P.S. Turn the water off at the toilet and flush before you start driving, because the water will spill out of the tank, but not the bowl.
John the 310 seal is around twenty bucs online