Jestersix

pH probe calibration problem

mediumrare

mediumrare

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Has anyone here used the following calibration solution? (Expiration mid 2018)
https://www.amazon.com/gp/product/B007X5J9L6/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1

I'm used to using the Hanna instrument single use packets of calibration fluid, but wanted to try something more efficient.

Compared to my red-sea pH test kit, the water pH reads ~7.75 on the probe and ~8.2-8.3 on red-sea pH test kit. My alk is low right now ~7 (still dialing in the dosing), so the calibrated pH may be right but i have no idea. Im expecting other calibration fluid and new liquid pH test kit to verify but just wanted to check in here.
 
Also decided to just go for it and order Thermo Fisher calibration buffer. Stupid expensive, better be worth it.
If the probe is dying again that'll mean its only lasted ~6 months.
 
I use the brand of solution in your first post, never had issues with it except for with my last probe, I couldn't get it to calibrate within range so I chucked it, next probe calibrated with same solution and I get 8.1-8.2ph reading throughout the day, only way for me to verify is with API PH test which also yields numbers within a ballpark of my probe. Not a whole lot of info but thought I'd share what I've experienced, hopefully it helps....
Where do you live? wouldn't mind comparing solutions/probes :)
 
HiFidelity said:
I use the brand of solution in your first post, never had issues with it except for with my last probe, I couldn't get it to calibrate within range so I chucked it, next probe calibrated with same solution and I get 8.1-8.2ph reading throughout the day, only way for me to verify is with API PH test which also yields numbers within a ballpark of my probe. Not a whole lot of info but thought I'd share what I've experienced, hopefully it helps....
Where do you live? wouldn't mind comparing solutions/probes :)
Click to expand...
Im in the Oakland hills. The pH probe i am using was purchased at the end of Feb this year. I realize that pH drift may occur, but it was just shocking that before the calibration yesterday the pH was in the 8.3-8.4 range, and after calibration, it dropped to 7.7, with red sea pH test reading ~8.2-8.3.
I'll have the thermo fisher pH buffer next week, and the Hanna buffer tomorrow. Plus I ordered some pH test strips just for the hell of it.
 
Have you cleaned it really well?
Soak in vinegar for a few days, then soap + water, then soak in tank water for a few days.
After all that, THEN re-calibrate.

Probe should last a lot longer than that. Might be calcium deposits or other crud.
 
rygh said:
Have you cleaned it really well?
Soak in vinegar for a few days, then soap + water, then soak in tank water for a few days.
After all that, THEN re-calibrate.

Probe should last a lot longer than that. Might be calcium deposits or other crud.
Click to expand...
I did soak it in acetic acid (5%) for a bit before re-calibrating it second time, but no change.

Never heard of using soap. can you provide justification for soap vs just vinegar and RO water?
 
I just rinse mine in RO water before & after calibration. I've had to recalibrate my probe about 4 times now since I bought the solution and everytime the PH reading dropped after each calibration so your findings are similar to what I've seen in terms of probe drifting.
 
HiFidelity said:
I just rinse mine in RO water before & after calibration. I've had to recalibrate my probe about 4 times now since I bought the solution and every time the PH drops after calibration so your findings are similar to what I've seen in terms of probe drifting.
Click to expand...
how often do you calibrate?
 
mediumrare said:
I did soak it in acetic acid (5%) for a bit before re-calibrating it second time, but no change.

Never heard of using soap. can you provide justification for soap vs just vinegar and RO water?
Click to expand...

Solid justification : No, not really.
The general idea is to use different cleaners for different crud.
And I have read recommendations that say vinegar, and recommendations that say soap + water.
Vinegar alone is likely fine.

Thinking more, really should be the other way around anyway. Soap and water first.
 
Update

So I've been running a brand new Neptune double junction pH probe since mid July. I had initially calibrated it with the mystery Amazon calibration buffer (see OP) and it was reading ~7.7 after calibration. After re-calibrating based on hanna buffer, the pH read between 7.83-7.95 (for the past 2 weeks).

Well, i finally got around to the Thermo Scientific lab grade buffer, and following calibration last night, the pH topped out at 8.12 last night (once I establish a new trend, ill post those figures).

edit: after calibration the pH probe red 7.00in the 7.00 calibration buffer and 9.99 in the 10.01 calibration buffer (temperature compensation turned off).

In any case, this new figure of 8.12 at normal peak pH time lines up more consistently with the red sea pH test kit (reading around 8.2 depending on how color blind one is). And since I have higher confidence in Thermo Scientific as they supply research and industry labs I finally feel a little more certainty in my pH measurements.

For anyone interested I ordered the 7.0 and 10.0 Thermo Scientific Orion Buffer from Cole Parmer (you have to buy each pH individually)
http://www.coleparmer.com/Category/Thermo_Scientific_Orion_pH_Buffer_Solutions/59274
 
I just went through this and soaked my probes in vinegar/scrubbed them to get all the deposits and algae growth off of them. I used the individual Pinpoint 3-pack to recalibrate the pH and ORP probes. Seemed to have gone well (pH was reading overly high, ORP overly low).

https://www.amazon.com/gp/product/B00DEPJEL4

I feel good about the calibration results. You pay a premium for the small packets of fluid vs. the larger bottles, but it's nice to know the fluid is fresh each time you use it.
 
wpeterson said:
I just went through this and soaked my probes in vinegar/scrubbed them to get all the deposits and algae growth off of them. I used the individual Pinpoint 3-pack to recalibrate the pH and ORP probes. Seemed to have gone well (pH was reading overly high, ORP overly low).

https://www.amazon.com/gp/product/B00DEPJEL4

I feel good about the calibration results. You pay a premium for the small packets of fluid vs. the larger bottles, but it's nice to know the fluid is fresh each time you use it.
Click to expand...
how old are your probes and are they single or double junction?
 
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