made this post 5/10/07:

Ahhh, the mellow, friendly vibe of the PoolForum. So nice to be back. Course, I wouldn't be here reading if there wasn't just the teensiest little problem of my own. Hmmmm.... Vitamin C tablets, eh? Wouldn't hurt to have a little stash of those around the house anyway, and they're certainly not very expensive.

So. My pool man (me) did the ascsorbic acid treatment on 5/12/07. The stain did LITERALLY vanish before my eyes. Freakish, bizarre. I was slowly working around the pool edge dropping the powder in and I happened to look up before I was even finished going around and a large area opposite was already clear! So.

But today I wanted to say this: yesterday, May 24, was the first day I did not have to dump in chlorine (bleach), ie, did not have a zero reading. (I did follow instructions and put in the amount I believed correct according to the "best guess" chart - in my case about 8 ppm.) that means it took 13 days for the pool to stabilize with respect to chlorine. Does that sound right? Everything appears to be just as happy as a clam now. All the other values are fine. I should mention that my Ph behaved perversely according to what I read here - it never went down. I do not have a good tester, but the color on a test strip indicates a strong Ph, around 7.6 or higher. Now that the chlorine has settled down I plan to go to the pool store and have a test done. I'd appreciate any comments....

I still can't believe the way that stain disappeared

PS how do I lower Ph without lowering total alkalinity? would appreciate a helpful nudge from anyone on this question...