I need recomendations on which sealant to use when re-installing a flusher fitting to my black water tank. I have traced a slow drip from my black water tank to the point where the flusher fitting it attached to the tank. When the sewage reaches that level it slowly leaks around the outer edges between the fitting and the tank, runs to the lower part of the tank, and drips to the ground. I'm lucky that I found it. I've got the "belly shield" removed to install a Drain Master electric valve on the tank, otherwise I wouldn't have seen the leak. The flusher is at the opposite end of the tank from the drain valve, but I needed access to run the wires for the Drain Master valve. This is on an '02 Holiday Rambler Presidential, in case that matters, and the black water tank is black/charcoal in color. The flusher fitting is black plastic. One neighbor, in this RV park, recommends Permatex Black Silicone adhesive sealant (16BR) that's sold in automotive parts stores. I just want to make sure that I don't create a problem for myself when I do this repair. And, I certainly don't want to ever have to do it again!!