OK let me start off by saying I have been lurking for a while but finally had a reason to post. One of my gray water tanks had the pipe break off in the fitting at the tank. I'll spare you the stor...
If you have about 1.5 inch stub you could use a coupling. I am guessing it is 1.5 inch pipe. A rubber coupling with hose clamps would/could be the easiest. Should be able to find at hardware store. Something like this: Fernco
