QUOTE "Same here. Took mine completely apart two seasons ago and changed all of the seals. Not a problem since. Before that, had a small leak from somewhere around the base that I could not pinpoint nor get stopped for anything. After the dis-assembly and re-seal, no problem since. Believe it or not, I was able to get the seals off-the-shelf, at Camping World. My Sealand is the Model 511 PLUS.
However, if the OP is referring to the water in the bowl leaking out, than that's a different issue all together. If changing that seal, you should use a good coating of plumbers grease for sure. OR there could be some sort of a problem with the flush "ball" valve (I don't remember exactly what they call it) in the bottom of the bowl that closes the water in. Perhaps a small crack in the plastic "ball" valve that could be allowing the water leak out through it."
Interesting. I used the grease on the flange between the floor and the bottom of the base. When I replaced the thin gasket thingy between the base and the seat, just set it on there with no grease or nothing. I did take the time to go over the "ball" portion with a non abrasive scrubber before I put the gasket and seat on...for what it's worth.