I went by the RV dealer I used to work at yesterday. They were already sold out of the stuff. I asked the owner about it and he told me he had never used it but that Thetford makes good products and I might want to try it. My only concern is, if I understand you, you pour it in and let it sit. I seems like it would work on the top of the top seal, but I don't understand how it works on the bottom or inside the groove of the seal. When I have sprayed in the past I always open the valve and sprayed all over the seal. I do appreciate your input and I bet you a dollar I will end up trying it after my next stop at Camping World.