Yesterday I noticed that there is a leak on the top of my pump, where (I think) the discharge tubing is. I guess that's where all my pool water was going! I unscrewed the PVC nut that holds the pipe in place, but couldn't see any reason for the leak - no cracks, everything seemingly intact. The water appears to be mostly coming from underneath the nut. There's a picture below where you can see the evidence.
I didn't take a picture of it with the nut moved, but the tubing ends with a little bit of a lip and the nut threads onto the pump holding the pipe in place. It may be worth saying that when I lifted the nut, there was brown liquidy stuff smearing on the pipe, like something had dissolved under the nut. Old seal, perhaps?
It seems like if I can find a way to seal the nut, everything should be okay. I just don't know what to use to seal it and if this would even be a good idea. The only other helpful posts I found here and elsewhere that related didn't seem to have a nut like mine does. Do I need a rubber gasket? Some kind of sealing gel? Total noob who inherited this pool from a previous homeowner, so anything you can offer, no matter how insignificant, could help.