pH Probe inaccuracies?

[Siberwulf]

Hey folks, getting my pH probe setup today, and seeing some off readings. For context, this is a new tank, with 50 gallons of saltwater from my LFS and 40 gallons from my own brewing. I filled it on Sunday (day and a half ago). I calibrated my pH probe and things checked out. I stuck it in the tank (after a rinse) and it's showing a pH of 8.89, which feels high for how new this system is.

I grabbed my Red Sea test kit and ran a quick test of pH and it came back at a clear 8.2, which feels a lot closer to what I'd expect. Has anyone else seen this? I used Auto Calibration and all the indicators were green. (Water Temp is 79.1 btw)

Thanks in advance!

 

[Siberwulf]

Annnnd just realized I didn't place the calibration solution packets in the tank before I did the calibration. Would that cause things to be off that much?

 

[bdunn13]

Yes . The recalibrate.

 

[Siberwulf]

Yes . The recalibrate.

So I got some more solution, and did it the "right" way this time. Now the pH is coming in low at 7.74... I tested it with the Red Sea and it's still at 8.2.

 

[bdunn13]

What are you dosing or doing to get your PH up? Before I got a CO2 scrubber and started using Kalkwasser, my ph was 7.74 or less.. If you are not doing anything else, I would trust that number...

Get 1 more testing method to be sure which is accurate