Hi Everybody, first post here. I've purchased a home with a pool (see sig.) and I've never been a pool owner. We just finished opening up the pool for the season and I think it went okay. Everything appears to be in working order and the pool is clearing up with the help of the BBB method.
There is only one thing. I'm not sure what this mystery hole in the side of my pool is. It has a plug cover on it. It didn't have any air in it this winter, so I don't think it was winterized. When I unscrew the plug nothing shoots out or sucks in - it does nothing that I can tell. By my filter/pump there is a pipe sticking out of the ground - could this be what it is connected to?
What is this thing?
I've attached pics for reference.