Hi everyone.

I am replacing my IG pool liner. It was coming away from the coping and it didn't have enough elasticity for me to do the boiling water method to put it back in the track. Underneath the liner, I think it's a vermiculite bottom. It has algae all over it.
How do I clean this off and patch the areas that came off when I pulled the liner up?

Also can I paint the bottom with something to keep the algae from growing again? like waterlok for basement walls?