trouble with pH probes

[mcs]

I do not know what I am doing wrong. I have tried to recalibrate my apex pH probe twice and it is reading unbelievably low numbers. I used the Milwaukee calibration fluids, 7.01 and 10.01. I followed the instructions on the bulk reef supply instructional video. We are lucky enough to live in Miami, so the temperature of the room was 78 degrees, the tank was likewise 77-78 degrees. The probe reads the calibration fluids within 0.02, but is reading the tank at <8. I am running Kalkwasser, the alkalinity that I checked with my Hannah checker was 11.6. I have a handheld probe that I had not calibrated in some time which read 8.35-8.4 before I calibrated it with 7.01 and 10.01 fluids. After which it as well read below 8. (different packets of calibration fluid purchased at the same time). I have a seneye in a different qt tank that was reading 8,36, when tested with the handheld probe before calibration the reading was similar reading, after calibration it read <8.

 

[Randy Holmes-Farley Verified Community Expert]

The pH could easily be below 8. Often as low as 7.8 in a closed home.

I don't see any reason to suspect an issue, but sometimes there can be electrical interference, so to diagnose that, one can try reading the pH in a cup away from tank lights and pumps.

 

[bhavy]

This may not help much but I was told by Neptune to always calibrate in 'manual mode' rather than automatic calibration mode.
My other question would be after you calibrate your probes and test tank water, if you were to dry probe and stick back into calibration fluid 10 or 7 ,how close to 10 or 7 does it read?

 

[pmoneyt]

How do you Calibrate the probe in manual mode?

 

[bhavy]

When u go to the options under ph probe click on advanced then scroll down to manual calibrate

 

[mcs]

Thank you. The pH reads the same in a cup outside the tank and the probe does read the calibration fluids accurately. The only confusing thing is that the pH reads 8.3 with the API kit. I am getting 7.9 with my probe. With a normal dKH and a low pH, I guess that I should open the windows and ventilate. d

 

[Randy Holmes-Farley Verified Community Expert]

Thank you. The pH reads the same in a cup outside the tank and the probe does read the calibration fluids accurately. The only confusing thing is that the pH reads 8.3 with the API kit. I am getting 7.9 with my probe. With a normal dKH and a low pH, I guess that I should open the windows and ventilate. d

pH kits generally are not (edited to add not) worth using, IMO.

 

[bhavy]

I have a BRS co2 reactor (scrubber) . It raised my ph .2 during the winter. I have to mention I cut a 1" hole in my basement to the outside and plumbed 1" pvc to the reactor . Then the other side of reactor runs to my skimmer air intake. I can show a pic with more details if you need

 

[JimWelsh]

pH kits generally are worth using, IMO.

Is that really what you meant to say, @Randy Holmes-Farley, or is there a "not" that went missing?

 

[Randy Holmes-Farley Verified Community Expert]

lol

Right. Not worth using