I was thinking about using cement in another post. After sometime I decided againist it. It's my understanding, I would have to completely clean the ledge rock to get the cement to adhere. Cleaning the ledge in itself would be an impossible task given the location at the bottom of the pool with water seeping in.

My plans are to open up the ledge area and pump/drain all the water I can from the area. I would then back fill the hole with dried clay and compact it with the excavator bucket, hoping to stay ahead of the water coming in.

I'm having a difficult time finding someone in my area that has clay to sell.