Big drop in TA, big spike in CH...I'm confused

[steveinaz]

I just figured the only variables from past pool experiences was the act of leaving the cover off all Winter, and use of the Scale Free from Natural Chemistry. I'm never one to use "additives" in my pool besides chlorine, salt, and muriatic.

Thanks all for the suggestions. I will definitely allow pH to drift up more, not difficult to do here; and maintain a higher pH in the future. We're looking into a water softener as well as we already have the loop and drain available in the garage.

In the past pools (2 prior to this one) I would typically do partial drains (about 20%) at the end of each swimming season to address exactly what Matt is talking about (calcium creep). It's a "pay me now or pay me later" proposition in Southern Arizona.

 

[steveinaz]

10 days later, no acid added since 17 March:

FC=3
pH=7.6*
TA=50
CH=not tested (825ppm on 17 March)
CYA=not tested (70ppm on 17 March)

*When I'm looking at the color matching on pH (Taylor 2006 kit) it appears to be 7.8; however, 1 drop of acid demand brings it down to 7.4. Can you "back into" a pH reading this way? This is how I arrived at 7.6.

 

[JamesW]

The pH should be what it looks like. Do you have a picture of the test?

What are you keeping the CSI at?

 

[steveinaz]

CSI right now is -0.19 w/60degree water. Disregard, the pH is 7.8.