Need help identifying fitting

[crowfive]

I have a vinyl pool with fiberglass stairs. There is a fitting on the stairs that needs a gasket replaced as it's rotting, but I can't figure out what the fitting is. This fitting is hooked up to be used to add water to the pool, but I also have no idea if that's what its intended purpose is. I'm posting some pictures and some measurements in the hopes that someone here will know what I should be looking for as far as a gasket and if I should be able to remove the fitting? I'm hoping it will unscrew, but I haven't attempted that yet since I don't have a replacement gasket. Ideally I would replace the fitting as well since it's looking pretty janky. Here are the pics:




Measurements for the fitting are:

• Opening: 7/8th
• Flange diameter: 1 5/8th

If anybody has any insight or information on what I should be looking for I'd really appreciate it.

 

[JamesW]

It's probably an air intake for the return to the left. Don't try to remove it as any force will likely cause a leak.

 

[crowfive]

It's probably an air intake for the return to the left. Don't try to remove it as any force will likely cause a leak.

It's used as a water fill for the pool and its hooked up to a sprinkler valve. If I shouldn't remove the fitting, how would I change the gasket on this?
edit: grammar

 

[JamesW]

If I shouldn't remove the fitting, how would I change the gasket on this?

Do you need the gasket?

Maybe just use silicone if you want to create a seal.

 

[crowfive]

Well, with the gasket, I was just trying to replace what was there. I guess I could just use silicone to seal it, but is that a viable solution and something that is commonly done? Mostly, I just don't want it to look as bad as it does with the rotten rubber smearing everywhere.

Do you think there really isn't a way to replace that fitting easily since the fitting isn't looking that great either?

 

[wireform]

Don't touch it as the picture clearly shows a full crack. Do the silicone thing and call it a day.