Pinpoint pH monitor/probe - not trusting calibration

[NanoTopia]

So I decided to calibrate my pinpoint pH monitor again (it had been 6 months). I did a two part test pH 10 and pH 7 using pinpoint sealed calibration liquid. I was methodical with the calibration procedure as always. After calibration my tank water reads pH 7.9, it was always higher than that, pH 8.1-8.3. I dose Brightwell's Alkalin8.3-P for alkalinity and haven't noticed anything abnormal with my reef. I am keeping my ALK around 10 dKh.

 

I decided to check my pH with a Hagen colorimetric kit I had on hand, it read 8.3 (ish), where it should be. However, I am not really trusting the colorimetric test either as it is a year old and well..it's made by Hagen.

 

So, I am wondering if anyone has had issues with the pinpoint pH monitor/probe, could it be the calibration liquid, or malfunctioning monitor/probe? I used to use a pinpoint temp monitor but but stopped using it when I discovered it was out of calibration by 0.5 F (no way to calibrate it).

 

I guess I am off to the LFS to buy another pH kit, maybe Elos for a third opinion. I would be interested to know however, if anyone has had problems with this unit and calibration or any other thoughts.

[Deckoz2302]

How long did you wait for it to stabilize while it was calibrating in each solution. Did you rinse the probe in rodi before and after each solution?

[NanoTopia]

Probe was in each solution for about 3 minute each. Probe was rinsed between solutions. Numbers were stabilized for quite a while.

[jfarabaugh]

I used to worry about PH and would go through the trouble of trying to calibrate it. Best thing I ever did was throw it away and focus on correct and stable parameters through dosing. That was over a year ago.

This is unless you are running a calcium reactor or you are kalk dosing... I do not use either but I think you want to run a PH monitor in those cases.

 

my .02

[NanoTopia]

I used to worry about PH and would go through the trouble of trying to calibrate it. Best thing I ever did was throw it away and focus on correct and stable parameters through dosing. That was over a year ago.

This is unless you are running a calcium reactor or you are kalk dosing... I do not use either but I think you want to run a PH monitor in those cases.

 

my .02

 

I agree with the stabilization aspect, but I spent $100 on a tool that is useless if I can't trust the reading it gives. I would like (for peace of mind) to know where my parameters are at. I am a nurse and rely on labs in my profession, this will eat me up if I don't resolve it. I think I will try another calibration using new calibration fluid and buy a colorimetric test kit and check it that way also.

 

I do wonder how many times reefers react to false readings that result in messing their tanks up. I need testing equipment that works and is accurate or I see not point to own test kits at all. Before I react to a pH reading of 7.9, I need to know it is really 7.9. I would like my pH to be in NSW value (8.3). Just the way I am with things.