Lately, I seem to be in a constant battle of adding 50 - 65 oz of baking soda every week to keep my TA around 60 (the low end of my target range of 60 - 80). And by the time I add, it's dropped to 45-50. Then, after I add it and get my TA back to 60-65, I find myself adding more acid than when the TA was down around 50. So, I feel like I'm in a constant back and forth between adding baking soda, then adding [more than normal] acid. As the temps drop, I'm going from about 100 oz of acid per week to about 140 oz per week. It's starting to occur to me though that maybe I should really just be focusing on CSI, which considers both pH and TA (as well as CH, CYA and Temp), instead of just keeping the pH between 7.5 - 7.7 and TA between 60 - 80 (and it's never above 65).
For example, today my numbers (before adding acid...I do that in the evening) were: FC: 6.5, pH: 7.9, TA: 60, CH: 275, CYA: 36, Temp:52°F, CSI: -0.19.
But if I were to shoot for a pH of 7.5 and add 28 oz of acid tonight, my CSI would drop to -0.53, which would border on the "Corrosion" warning at -0.6. Also, adding more acid is driving down my TA. Conversely, adding more baking soda is driving up my pH.
I know it doesn't help that I still have a residual Borate level of 30 (I learned the hard way that adding Borates drastically increases acid consumption), so I'm slowly waiting for that to drop to 0 one fine day probably 2 years from now. I also know the colder temps aren't helping right now either.
Anyway, has anyone else experienced similar see-saw effects with pH and TA? Am I wrong to use CSI as my guide for whether or not I truly need to keep my pH and TA between the ranges mentioned above? In other words, I guess what I'm considering is (for my current water temperatures around 52°F) letting the TA hang around 45 - 50 and pH at 8.0 - 8.1, which would put my CSI at -0.25 or -0.19 (similar to above). This would allow less addition of both acid and baking soda (saving $$$ and time), while yielding the same (or more neutral) CSI. Basically, at the end of the day, isn't it all about having a good CSI reading or can high pH and low TA readings on their own cause issues?
For example, today my numbers (before adding acid...I do that in the evening) were: FC: 6.5, pH: 7.9, TA: 60, CH: 275, CYA: 36, Temp:52°F, CSI: -0.19.
But if I were to shoot for a pH of 7.5 and add 28 oz of acid tonight, my CSI would drop to -0.53, which would border on the "Corrosion" warning at -0.6. Also, adding more acid is driving down my TA. Conversely, adding more baking soda is driving up my pH.
I know it doesn't help that I still have a residual Borate level of 30 (I learned the hard way that adding Borates drastically increases acid consumption), so I'm slowly waiting for that to drop to 0 one fine day probably 2 years from now. I also know the colder temps aren't helping right now either.
Anyway, has anyone else experienced similar see-saw effects with pH and TA? Am I wrong to use CSI as my guide for whether or not I truly need to keep my pH and TA between the ranges mentioned above? In other words, I guess what I'm considering is (for my current water temperatures around 52°F) letting the TA hang around 45 - 50 and pH at 8.0 - 8.1, which would put my CSI at -0.25 or -0.19 (similar to above). This would allow less addition of both acid and baking soda (saving $$$ and time), while yielding the same (or more neutral) CSI. Basically, at the end of the day, isn't it all about having a good CSI reading or can high pH and low TA readings on their own cause issues?