She will let me test her water, I did the PH before for her. It was around 7.2. She added alkalinity up to fix it, lol. Before that, earlier in the season, it was 7.2 when I tested it for her, and I gave her some Borax and told her it was PH up. Once I was curious as to what the chlorine level was, I took my OTO and got as ample when she wasn't home. It was probably around 10, she had just "shocked". The pool store had her CYA around 55at startup last month, I saw the repot. I've tried to tell her about TFP, but she doesn't "get it". I don't think she would easily understand it, either. I did send her the link for DE filters, as I read about them, and she bumps her filter with it on. I think her TA was 80 before she adjusted it, but I have no idea how much stuff she put in.
He will just have to have good excuses not to go in their pool. That means they'll be in my pool, lol. Most of the time I don't mind.
My son's GF's family came over to swim and her mom commented how gorgeous the water was. I told her I'm obsessed, ha. And I told her, briefly, all about TFP. She thought it was pretty cool!