Well I closed the pool as normal in the fall and when i removed the cover the water has drained all the way to the deep end. I'm pretty sure its the main drain now.

Got a pressure test scheduled for this week. I'm really hoping its around the drain and not in the pipes. The pool guy is recommending that I plug the main drain if its in the pipe. I really dont want to do that because i know that my pool depends on the main drain to remove a lot of the debris at the bottom of the pool.