In a gunite pool we have several return port flanges leaking at the pool wall.
The leak shows itself when winterizing and blowing out the return lines with air. With the rubber stopper tightly in place, a lot of air leaks between the flange and the pool wall. Clearly if left unaddressed, pool water will re-enter the return pipe and we no longer have winterized pool return lines. This matters because we have hard wintertime freezes in our area! Draining the water below the ports won't help for certain, as lots of rain can easily refill the pool to that level.
With gunite and plaster walls are we better off with silicone "glue", some kind of epoxy or what, trying to seal that outer flange to the pool wall?
We're not thinking about plain silicone, but the 'silicone glue'. Or maybe the two part putty-like epoxy, or maybe the usual two part epoxy that is runny, though that seems unlikely as, there is nothing to keep that from dripping off the fitting.