Kh director values are off

[arvind]

So I got the kh director configured and has been running for few days and reading close to a Hanna checker that I used to validate the kh values. I recently got the GHL kh reference solution and it was reading at 7.7 which is close enough for me. Now suddenly the kh values shot up a day later. I see a difference of .7 dkh for no apparent reason. Can the ph probe be off in less than a month? Or Should I recalibrate my sample size again?

Also, can I calibrate the ph probe with any brand reference solution or is it designed to work with only the GHL ph reference solution?

 

[Vinny@GHLUSA Verified Sponsor]

Sudden jumps can sometimes be caused by air bubbles making their way into the sample tube.
The pH probe must be calibrated with low range fluids, 4 and 7.

More troubleshooting tips can be found here:
https://www.aquariumcomputer.com/knowledge-base/kh-director-tips-and-troubleshooting/