Something is bleaching my liner

[Metalman23]

My liner has been getting lighter and lighter near the stairs all year, I thought I was seeing things at first, but then it became undeniable, I don't dump chlorine in on the shallow end, is it the sun bleaching the liner? Should I be concerned about it? What can I do

 

[JamesW]

Maybe the cleaner grinding away or the tab floater sitting near the wall and dropping chlorine straight down.