[ Upgraded membership; moved thread to "AG pool" section <= you may need to log out and back in, before you can see everything.

BTW, I happened to ask another pool expert about your situation -- he's ALSO not an AG installer -- and he suggested I warn you that it may be more practical to replace the pool, or at least the liner and part of the wall section. I thought about it, and agreed. Neither he nor I know -- partly because of lack of experience, and partly because you pictures don't show everything necessary. But it would be better to keep that possibility in mind, before you spend hours and hours and many dollars trying to repair it.

Also, if a leak didn't precede the failure (washing out the base) then the problem was quite possibly caused by substandard installation.