I got some several small stains on the steps which resemble the bigger ones I have failed to get rid of at the deep end.
1) Bleach poured on stain did nothing (not organic?)
2) Vitamin C tablet laid on stain did nothing (not metallic?)
3) Vitamin C rubbed on stain did nothing (not metallic?)
4) Stain is dark brown, and you cannot feel any difference in texture at stain (not calcium deposit?)
I have a lot of berries that drop into the pool from nearby trees. I'm thinking the pigment in these berries may be doing this, but I don't know how you would get rid of that.
I don't know what to try next. Should I try Jack's Magic Stain iD Kit?