Pool Slide and Phantom Line

[illtiger1]

This is a strange situation, but I'll go ahead and hope someone can help. I just bought a house with an inground pool last winter so this is my first time closing. I have my return lines and skimmer line blown and plugged. When I blow out my return lines through the top pipe connected to the filter valve, water comes out of a small plastic pipe underneath my disconnected pool slide. I have no idea where this water is coming from or what its functin would be.

Also when I was blowing the lines, I noticed a line hole in the pool about 7 inches below where the slide is that seems to have no function. When I first opened the pool, it was plugged but seemed to serve no function all season. I blew air directly into it and nothing I could see occurred. Just to be safe, I sucked any possible water that might have been in there and plugged it ASAP. If anyone has a clue, please let me know. Thanks.

 

[spishex]

The slide has a water line so that you can run water down it for that good slip n' slide action. Not sure why it's not connected. Maybe the slide they put in isn't plumbed but they had the line already there?

The other port could be any number of things. If it is centrally located in the pool I'd imagine it is a dedicated suction or pressure line. No unexplained valves or stubs out at your equipment?