Mustard Algae? Or chemical stain?

Yea, I don't like you using pucks with your CYA that high

Did you try using a vitamin C tablet on those stains? I might have missed it...

Great, thanks for the info. I guess since I have about 90, of have to get rid of half my water to even get to 45, right?

Good to know that brushing didn't do much, because I've been brushing and there's literally no change.

Here's a random question-- anyone know how expensive a new pool liner installed is? Many thousands?

Vitamin C? Never heard of that. The same pills we eat? Does it matter if chewable or not? I'm serious. Really never heard of that technique, but I guess you're just rubbing citric acid into it, huh?

Yup. Actually ascorbic acid. Just the pills you get at the pharmacy. Get the tablets. And yes, half the water to dilute by half.

My liner cost many thousands but I have an inground 27K pool. Don't know about the cost for AG. You could probably get a quick quote for AG.