Measuring Kalk Stirrer pH - Worth It?

[dangles]

I've noticed the pH and dKH in my tank tend to start drifting down as the kalk in my stirrer depletes. Is it worth getting a probe to continuously measure the kalk in my stirrer to try to maintain ~12.0 pH? How long can I expect to get out of the probe in the super alkaline environment? It may be more hassle than it's worth, but maybe not.

 

[John Neuzil]

I've noticed the pH and dKH in my tank tend to start drifting down as the kalk in my stirrer depletes. Is it worth getting a probe to continuously measure the kalk in my stirrer to try to maintain ~12.0 pH? How long can I expect to get out of the probe in the super alkaline environment? It may be more hassle than it's worth, but maybe not.

Ive been wondering the same

 

[Randy Holmes-Farley Verified Community Expert]

I'd recommend a conductivity probe as a far more sensitive and accurate way to measure kalk potency.

Saturation is around 10.3 mS/cm, and potency is linear with conductivity.

pH is a crude measure, being both logarithmic, and of dubious accuracy above pH 12 when calibrated at pH 7 and 10. Best way is to measure the pH of truly saturated kalk (say, 2 teaspoons solids in a cup of RO/DI) and compare that to the kalk of interest. A difference in pH of 0.3 units is about a halving of potency.

 

[dangles]

I'd recommend a conductivity probe as a far more sensitive and accurate way to measure kalk potency.

Saturation is around 10.3 mS/cm, and potency is linear with conductivity.

pH is a crude measure, being both logarithmic, and of dubious accuracy above pH 12 when calibrated at pH 7 and 10. Best way is to measure the pH of truly saturated kalk (say, 2 teaspoons solids in a cup of RO/DI) and compare that to the kalk of interest. A difference in pH of 0.3 units is about a halving of potency.

Awesome thanks Randy.

Something like this?

 

[Randy Holmes-Farley Verified Community Expert]

I’ve never seen that one before, but yes. It has the right range.

 

[Sisterlimonpot]

My setup for kalk uses a pH probe to monitor the pH inside the reactor. It alerts me when the pH drops to 12.35 and that tells me it's time to replenish the reactor.

I agree with Randy's concern to not use a pH probe that is calibrated to 10 as the high range. I calibrate between 10.00 and 12.46.

I haven't had much experience using a conductivity probe to monitor pH. So, I can't help with that.

 

[dangles]

I’ve never seen that one before, but yes. It has the right range.

Is there one you’d trust and/or have experience with?

 

[Randy Holmes-Farley Verified Community Expert]

Is there one you’d trust and/or have experience with?

Yes. For all around reefing use, I'd get a used high end conductivity meter and preferably a 4 electrode probe. Sometimes they can be had at ebay for not that much. I use an old Orion, like this one, although i can't find the exact specs for that probe tip, but I expect it will work if the device is functional:

https://www.ebay.com/itm/3757550848...2047675&ssuid=&widget_ver=artemis&media=EMAIL