I have a question on the return line on my agp. I have a Hayward Outlet with the adjustable eye. I'm closing for the winter and trying to figure out how to plug it. I have a few screw in plugs, but it does not fit when I unscrew and remove the adjustable eye. I have a key that fits inside.. Does the inside remove to add the threaded plug? I can't see the it because the cover is on and I'm reaching under the cover. I have searched but found no info.