KenM

Still curious about the Taylor test Thanks Nitro, the articles are great! I had found them, read them and have been following your advice the past month or so, in fact did your decontamination process, tested chlorine demand, and am using your dichlor/bleach method. My pH is much more stable with TA=50 ppm. I remain curious about the acid demand (or base demand) test. Does anyone find them useful? Do they only work in a certain range of TA? Taylor's testing guide book states "correcting pH is effortless through the use of either the acid or base demand test." Is this just hype?

Back to pH: what's going on with Taylor Acid Demand test? Thanks for the very useful information, this is helpful to me in my struggle to settle on a balanced tub. I made a couple more dry acid additions and managed to get pH down to 7.5. It is still tending to creep up, but now between 7.5 and 7.7 which makes me a little more comfortable. Now I am curious why the Acid Demand test does not give me a useful suggestion for lowering pH. It repeatedly suggested 0.7 oz of dry acid would get the pH down to 7.5 in my tub, and I never found that to work. In the end it took 8 to 9 times that amount to get pH to 7.5. BTW, after the last 3 additions of dry acid I measure no change in TA (to the resolution of the Taylor kit), it remains at 50, but pH is now responding.

Thanks Chem Geek. If I am using the Pool Calculator correctly, it tells me with TA=50ppm and CH=170, I need pH 7.8 - 7.9 for the lowest CSI. Is this what you are recommending? If I put 50 ppm Borates in the calculation, then the pH needed to minimize CSI goes even higher. Which is more important, keeping the right pH or the minimum CSI? Also I'm curious why Hotsprings recommends TA in the 125-150 ppm range, and quite a few suppliers recommend the 80-120 ppm range.

I guess I am also a newbie since I haven't figured out the chemistry. 400 gal Hot Springs Vanguard came with house purchased in 2006. For 3 years we enjoyed it, just used test strips to keep FC, pH and TA in recommended range. I've just had to replace the cover and lifter, and since I now have several hundred $ invested, I decided I would buy a Taylor K-2006 kit and do things right. Kit arrived about a week after refill. Measured levels at that point: CH=40, TA=50, pH=7.9. I first used Leisure Time Calcium Booster, aimed for CH of 150 but ended up with 170. I then focused on getting TA up, so added 4 oz sodium bicarbonate (SpaGuard Total ALkalinity Increaser). At this point I measured CH=170, TA=100, pH=8.0. I did the Taylor acid demand test, which said I needed 0.7 oz dry acid to get pH down to 7.5. I added the dry acid (using SpaGuard pH decreaser and measuring with a digital kitchen scale with 0.1 oz resolution), ran all jets for an hour then let sit for an hour. Remeasured pH with Taylor kit and got 8.0 again. I repeated this 3 times, with same result, no change at all in pH, although TA measurement was dropping. Taylor acid demand called for 0.7 oz dry acid to get down to pH=7.5, but adding this much gave NO CHANGE in pH reading. After 4th addition of 0.7 oz dry acid I finally got to 7.9. Three more cycles of adding dry acid I finally got to pH=7.7, this time I added 0.4 oz dry acid. Next day pH reads 7.9 again, with TA back down to starting point of 50 ppm. What is going on here? I started with pH=8, I have added 5.3 oz dry acid, incrementally over 3 days, pH is at 7.9. While the saturation index is pretty low with these numbers, that pH value seems pretty high. For the record, I am using Nitro's dichlor/bleach sanitation procedure. My CYA measures 30 using the Taylor K-2006. Should I be doing something different, or should I live with pH values that high?