Vinyl liner design wearing off

[jeffboer]

Have a vinyl liner that looks to have been installed sometime in 2016, based on documentation provided by previous owner. Patter on liner seems to be slowly coming off in spots. Not sure what could be causing this? Any chemical imbalance that would do this? Chlorine level? Older Dolphin robot I use?

 

[Newdude]

Any chemical imbalance that would do this?

Bleach or MA that were dumped in without being brushed around may have sat there. If it was granular shock (or similar) it would usually be a whole mess of bleached dots and not smooth over the whole area.

 

[Newdude]

*edit. I just zoomed in on the 2nd pic and that’s EXACTLY what you got there. A whole bunch of bleached dots. Granular.