Hello- we had our pool refinished last year shortly after Mother's Day. Since then we have been fighting a mustard algae and now we have small black spots showing up near the deep end. I have hyper shocked the pool and it clears up and then comes back. See my questions below- any advice is appreciated!
1. We now have Oklahoma flagstone, but did not have it sealed. Could this be a contributing factor to the mustard algae?
2. How can we treat the mustard algae?
3. Are the black spots black algae? I was able to scrape this off with a wire brush.
4. The steps now have some brown tint to them that will now go away- any advice? Guidance?
I can upload pictures tomorrow.