What causes these stains?

[Jmstange]

I'll admit that my pool care has been a little lax lately due to a new job and finally moving my things to the house Yada yada. But I always make sure this is chlorine and the cleaner runs almost everyday. That being said I have stains that weren't there when I was conscious. What might cause that? I have these baby acorn things that fall in the pool but nothing sits on the pool bottom for days. I have 0 cc. How do I clean these and avoid new stains.

 

[TO116]

Those little acorns fall in my pool all the time. They’ll stain if they sit there for a while, but once you remove them the stain should disappear the next day.

That’s how it works for me anyway.