Testing Ph with high Cl' levels?

[aylad]

When your chlorine is high, and you test pH, you usually get falsely high numbers. So if your chlorine is high and you're still getting low pH, I'd go ahead and continue the Borax additions. You can dilute your pool water 1:1 with distilled water, test that for pH, and still have a reasonably good result up to about 20 ppm with the K-2006. So in your case, unless Pooldoc, chemgeek, or some of the others have better suggestions, I would treat with Borax until you get at least 7.0, then wait for your shocking process to be over and let your chlorine come back down to normal before testing it again.

Regarding your question about how high chlorine levels can go, I will tell you that I've had my chlorine up to the 30-40 range in my liner pool for a 2-3 week stretch, with my CYA at 90 with no problem. Since your CYA is so much higher than mine was, I wouldn't think that 30-40 in your pool would be a problem for your liner, (assuming both liners are the same quality) since the CYA acts to make the chlorine less aggressive. I wouldn't dare raise it that high if my CYA was, say, 20, but your higher CYA level is what makes you safely able to raise yours that high.

Just for my clarification--your sig says your pool is gunite, but you have a liner?

Janet