"unusually" high TA and borderline CSI

[nabril15]

Hello all
The numbers:
FC 8, CH 325, PH 7.8, TA 120, CYA 80, Salt 3400, and temp of 88 F. I do not add Borates.

ON THE APP: CSI = 0.38 and "Greater than 0.3 suggests potential for scaling"
ON THE TFP pool calc page: CSI = 0.24, and my CSI is fine.

Which one should I pay attention to? And if I need to act, I will need to lower ph and then turn on my water feature to aerate, right? If I have to do this, should I aerate for 4 hours and then test ph? Or sooner than 4 hours?

Thank you

 

[reggiehammond]

With a SWCG, you're in the danger zone with high TA as your pH can rise quickly and scale can form inside the SWCG cell.
When pH gets to 7.8-8.0, use muriatic acid to target 7.2. TA will lower with these acid additions and your CSI will be negative (which is what you want to avoid scale.) After a few cycles, TA will be lower and pH will stabilize.

 

[nabril15]

With a SWCG, you're in the danger zone with high TA as your pH can rise quickly and scale can form inside the SWCG cell.
When pH gets to 7.8-8.0, use muriatic acid to target 7.2. TA will lower with these acid additions and your CSI will be negative (which is what you want to avoid scale.) After a few cycles, TA will be lower and pH will stabilize.

Thanks Reggie
But do I follow the csi from the app or the webpage? They're different.
Or do I ignore that difference in results and just bring the TA down?

 

[mknauss]

You have a data error in one of the calculation methods. They will result with the same CSI if all the data is properly entered.

 

[nabril15]

You have a data error in one of the calculation methods. They will result with the same CSI if all the data is properly entered.

Thank you Marty
I caught my error.

Now. I added 48 ounces of acid a few minutes ago with the plan to lower my erroneous CSI.
Obviously my pH should drop to 7.2, so I should aerate tomorrow to raise it, no?

 

[mknauss]

If your TA is 120, the pH will rise naturally. I would not do anything extraordinary.

 

[nabril15]

If your TA is 120, the pH will rise naturally. I would not do anything extraordinary.

Ok, so I shan't aerate?

 

[mknauss]

No need to.

 

[nabril15]

good morn from Norm
an update.
The ta is down to100, my FC is 10, so I cannot test the ph.
I shan't continue to aerate, right?

 

[mknauss]

You can check your pH at a FC of 10. Just do it quickly.

 

[nabril15]

You can check your pH at a FC of 10. Just do it quickly.

Thanks Marty
The fc is higher, and I just stopped at 20 drops = 10. I was just checking it to see if I could check the ph. We will be going out of town a few days, so I dumped some more chlorine than usual.

And what did you mean by "check it quickly"?

 

[mknauss]

If TA is 100, add enough acid to drop pH by 0.4.

 

[nabril15]

If TA is 100, add enough acid to drop pH by 0.4.

that's a lot of acid, wow, a half gallon.

 

[mknauss]

that's a lot of acid, wow, a half gallon.

What acid strength are you using? Should take about a quart of 31.45%

 

[nabril15]

What acid strength are you using? Should take about a quart of 31.45%

Yes, 31.45%. Pool math told me 27 ounces. Never mind.