Gasket or O-ring?

[drewspool]

Just discovered that the return jet fixture is leaking. The leak seems to be on the inside of the pool, water's coming out around the fitting. Previous owner used some kind of putty around it on the outside (thread side but not on the threads themselves) but that's all crumbled and nasty looking.
So, I'm figuring sealing it from the pool side, what would be better, a flat gasket so it covers more area or just an O-ring (assuming I can find the right size).
Or just use plumbers dope like the previous folks did?

 

[NWMNMom]

If it is an older used pool it is entirely possible that the gaskets are shot, brittle or damaged but you may even have a crack in the return fitting itself. I guess I would lower the water below the return, remove the unit and gaskets for inspection. You can order entire units with the gaskets for a pretty reasonable price. I wouldn't add more silicone or goop or whatever until sure there isn't some real damage.

 

[drewspool]

That was fast!
I did pull out the fitting, everything is intact, no cracks or damage at all, but other than that old "putty" there was no other sealant on either side.

 

[NWMNMom]

If it's all in good working condition then perhaps the gaskets are the only thing you need. However, some people will use the putty or silicone caulk around the fittings in addition to everything just for "backup" sealing. My DH likes to add the silicone caulk.