Quick Kalk Question

[Adamc13o3]

I have a PH probe in my Kalk reservoir. If the PH in the kalk is decreasing does that mean the potency of the alkalinity in the kalk is decreasing as well? It hasn’t gone down much, just from 12.5ish to 12.39. To be honest I am hoping that the answer is yes. As I need the PH boost way more than the KH.

Thanks,

Adam

 

[Randy Holmes-Farley Verified Community Expert]

Yes, a drop in pH is a potency reduction. pH is a log scale, so a drop of 0.11 pH units is about a 29% drop in potency. (It is actually a little worse than the simple log scale predicts, but unless folks really want to talk about the nitty gritty details, just assume it’s dropping by the ratio of the pH values raised to the power of 10.)

 

[Adamc13o3]

Yes, a drop in pH is a potency reduction. pH is a log scale, so a drop of 0.11 pH units is about a 29% drop in potency. (It is actually a little worse than the simple log scale predicts, but unless folks really want to talk about the nitty gritty details, just assume it’s dropping by the ratio of the pH values raised to the power of 10.)

Thanks

 

[Adamc13o3]

At what PH value is it not potent anymore?

 

[Randy Holmes-Farley Verified Community Expert]

At what PH value is it not potent anymore?

Well, every 1 pH unit drop is a factor of 10 reduction in potency.

 

[Adamc13o3]

But at what value does potency start?

 

[Randy Holmes-Farley Verified Community Expert]

But at what value does potency start?

The pH of saturated kalkwasser at 25 deg C is 12.45.

If you use pH for potency, which is much less accurate than conductivity, then do not just use the value you get. Directly compare it to known saturated kalkwasser.