Dietitian Posted February 18, 2010 Report Share Posted February 18, 2010 I keep my TA at around 40, is that okay? My pool calculator says the water is CSI balanced, but is there some other problem with keeping it low? I have borates in the water. Quote Link to comment Share on other sites More sharing options...
chem geek Posted February 18, 2010 Report Share Posted February 18, 2010 No, it's OK so long as you are not using acidic sources of sanitizer or oxidizer. For example, such a low TA would not be good if you were using Trichlor tabs/pucks (which you normally wouldn't use in a spa). The borates are great for preventing a rise in pH, but they have less capacity against a lowering of pH whereas the carbonate portion of TA is better for that. If you are using bleach (after initially using Dichlor to get the CYA up), then the 40 ppm TA is OK, assuming your CYA is around 30 ppm. If your CYA was much higher, then the TA would need to be a little higher. Quote Link to comment Share on other sites More sharing options...
Dietitian Posted February 18, 2010 Author Report Share Posted February 18, 2010 No, it's OK so long as you are not using acidic sources of sanitizer or oxidizer. For example, such a low TA would not be good if you were using Trichlor tabs/pucks (which you normally wouldn't use in a spa). The borates are great for preventing a rise in pH, but they have less capacity against a lowering of pH whereas the carbonate portion of TA is better for that. If you are using bleach (after initially using Dichlor to get the CYA up), then the 40 ppm TA is OK, assuming your CYA is around 30 ppm. If your CYA was much higher, then the TA would need to be a little higher. Excellent. What is the relationship of CYA and acidity? Quote Link to comment Share on other sites More sharing options...
chem geek Posted February 19, 2010 Report Share Posted February 19, 2010 Excellent. What is the relationship of CYA and acidity? Do you mean the relationship of CYA to the minimum TA level? Some of the CYA measures as TA in the TA test. At a pH near 7.5, about 1/3rd of the CYA level measures as TA. So if the CYA level is high, then the TA level should be higher since the carbonate portion of TA will be the TA minus about 1/3rd the CYA level. So having 40 ppm TA with 90 ppm CYA would have very little pH buffering since there would only be 40-90/3 = 10 ppm carbonate buffering and that is very low and likely to run out if you added any acid of any sort (say, dry acid or use of Trichlor or even Dichlor). Quote Link to comment Share on other sites More sharing options...
Dietitian Posted February 20, 2010 Author Report Share Posted February 20, 2010 Excellent. What is the relationship of CYA and acidity? Do you mean the relationship of CYA to the minimum TA level? Some of the CYA measures as TA in the TA test. At a pH near 7.5, about 1/3rd of the CYA level measures as TA. So if the CYA level is high, then the TA level should be higher since the carbonate portion of TA will be the TA minus about 1/3rd the CYA level. So having 40 ppm TA with 90 ppm CYA would have very little pH buffering since there would only be 40-90/3 = 10 ppm carbonate buffering and that is very low and likely to run out if you added any acid of any sort (say, dry acid or use of Trichlor or even Dichlor). Sweet, thank you. Quote Link to comment Share on other sites More sharing options...
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