Southern New Jersey - Moved in 3 years ago with old pool and salt

#1
Had an above ground pool for 15 years or more. Moved 3 years ago to a house which has an inground pool originally installed in the 80s I think. Steel walls and vinyl liner.
We are the third owners, and the second owners added a Pentichlor salt chlorinator. Which I love.
We are seasonal up here in jersey and just a few weeks ago had the concrete decking redone.

Which leads me to some problems and concerns... starting a post in the appropriate section.