The raised wall should we water proofed prior to setting this.

Sealers are not recommended for Limestone.

We use Indiana Limestone extensively for patios and coping without issues for years now.

Here's an article I wrote about Indiana Limestone and the proper setting methods.

https://aquamagazine.com/features/builder-blunders-failure-to-damp-proof-limestone.html

Thank you!!

How did your pool wall turn out? I have a similar wall and unfortunately the installer did not prep the stone, and I didn't ask enough questions. So I am in the process now of figuring out the best method to get it consistent and protected. It has started to show some splotchy marks.