The plastic holding tank for the head, on a boat I just bought, leaks around the lowest fitting. Looks like stress cracks around the connection, I would guess from a prev owner twisting it to try to get a hose off. Attempts to repair have evidently been made with some type of epoxy, but still leaks. Does anyone know of a sure & permanent way to repair this. I really don''t want to replace the tank, looks like a custom fit.