PH ISSUE. Need to get to the bottom of this

[jaime31]

@Randy Holmes-Farley

Hey Randy hope all
Is well and thanks for reading



I’ve been dealing with this PH issue for a few months and I know that if there’s anybody that can give me an accurate answer it would be you. Or anyone else can jump in and help out ofcourse



So I have an apex and my ph probe has been good for about a year now. Reading at the lowest 8.1 at night. And the highest was about 8.35 during the day and At one point at around the 14 month mark it would hit lowest 8.25 and 8.59. I found it a little odd so I decided to buy some Neptune calibration fluid (7/10)



Right before I started calibrating I was at 8.45 and right after it was done it dropped to 8.05!! I was not expecting that and immediately started to question the accuracy of the probe and also the calibration fluid. I put the probe back into the solution to verify the numbers and they came up accurate. But that wasn’t good enough so now I mixed a 1 gallon jug of kalkwasser and when mixed should read at about 12.5. To my surprise it actually ready 12.3. But for some reason I still don’t trust it and this is why..



Well for starters I tested using a Salifert ph tester and it came up at 8.5-8.6 on the color chart. Also I’m dosing kalkwasser, I have an oversized co2 scrubber, I run an algae turf scrubber 24/7 and also keep a ton of oxygen in the room from having my windows open measured by a co2 monitor. I just don’t believe that I’m only hitting 8.2 with all those factors



So my question is……



should I trust the ph meter?



Should I purchase another double junction probe?



Should I contact Neptune and see what they say ?



Also if anybody has other methods on accurately testing ph please let me know.



Thanks in advance

 

[KrisReef]

I share your frustration with finding a way to validate the accuracy of pH meters using calibration solutions and the results that often seem contradictory.

I have found a way to check lower pH’s when calibrating I use a small amount of wine to see if the pH is in the ballpark, as most are between 3&4 in pH. Of course I don’t get perfect results but I also finish off the glass or bottle that I use and then the results are easier to live with.

 

[Dread Pirate Dave]

Now that the probe is calibrated is it not good to go? But depending on the quality of the ph probe it may need to be replaced.

 

[jaime31]

Now that the probe is calibrated is it not good to go? But depending on the quality of the ph probe it may need to be replaced.

Loll I wish it was that easy! I’m not new to ph or even the hobby but the numbers aren’t adding up. If I can’t find an answer through Randy I’m gonna just buy a replacement double junction ph probe. Definitely not a Neptune one. I hear the pinpoints aren’t bad at all

 

[Salty_Northerner]

I have similar issues with my apex probe. It looks good and when I recalibrate it the pH is reading way lower. I find that just before I calibrate it I'll pin the reset button only for less then a second just so it turns off and boots back up. Once it's back online on my phone I'll manually calibrate it with TC enabled, only then I'm getting a good solid reading. I'll also clean the probe to be sure there isn't any crap built up on it. Also fully saturated kalkwasser has a pH value of 12.44 I believe.

 

[Garf]

Loll I wish it was that easy! I’m not new to ph or even the hobby but the numbers aren’t adding up. If I can’t find an answer through Randy I’m gonna just buy a replacement double junction ph probe. Definitely not a Neptune one. I hear the pinpoints aren’t bad at all

If you have some borax, you can do a cheap DIY solution that more closely matches pH of reef tanks;

Aquarium Frontiers Biochemistry of Aquaria

 

[Randy Holmes-Farley]

I would not expect a pH meter calibrated at pH 7 and 10 to read kalkwasser any better than the 0.2 off you see.

The hobby controllers seem to have a surprising number of issues with pH. It might sometimes relate to temp corrections, or the fact that the temp sensor may not make it into the calibration solutions.

In any case, after calibration, it is always worth checking to see if the pH meter can read both standard fluids correctly.

Note that the fluids can also be off, especially pH 10 which drops as CO2 enters.

 

[jaime31]

I would not expect a pH meter calibrated at pH 7 and 10 to read kalkwasser any better than the 0.2 off you see.

The hobby controllers seem to have a surprising number of issues with pH. It might sometimes relate to temp corrections, or the fact that the temp sensor may not make it into the calibration solutions.

In any case, after calibration, it is always worth checking to see if the pH meter can read both standard fluids correctly.

Note that the fluids can also be off, especially pH 10 which drops as CO2 enters.

Ok great thanks for the reply Randy much appreciated! That concludes my journey lol I’m gonna go get me a pinpoint and move forward from there.

 

[TangerineSpeedo]

If your probe reads correctly in the calibration solution, why would you question it. Also your salifert maybe reading different because it is not an electronic probe. Organics may come into play. If your skimmer is dirty that may come into play. I don’t think replacing the probe will help if your Apex probe is reading what your solution is saying what it is. That being said, I had a new Apex probe I struggled with for a year being off. Finally I bought a BRS one and it was accurate out of the box. The Apex one was never correct even after calibration.

 

[jaime31]

If your probe reads correctly in the calibration solution, why would you question it. Also your salifert maybe reading different because it is not an electronic probe. Organics may come into play. If your skimmer is dirty that may come into play. I don’t think replacing the probe will help if your Apex probe is reading what your solution is saying what it is. That being said, I had a new Apex probe I struggled with for a year being off. Finally I bought a BRS one and it was accurate out of the box. The Apex one was never correct even after calibration.

Yeah I just feel like something isn’t adding up.. a buddy of mine is having a similar issue but quite the opposite. So before calibration His ph is always usually low (L-7.75 H8.15) and after calibration (L8.35 H8.65)

He doesn’t run kalk
Doesn’t open windows
And skimmer is off most of the day (to control nutrients)
His at home co2 is through the roof and he’s borderline 8.7 keep in mind I took the same step with his as I did with mine. Rechecked calibration fluid and tested with kalk. But it’s still super high. We can figure it out and he also has the Neptune. We both gave up and are getting new probes lol

 

[Randy Holmes-Farley]

Yeah I just feel like something isn’t adding up.. a buddy of mine is having a similar issue but quite the opposite. So before calibration His ph is always usually low (L-7.75 H8.15) and after calibration (L8.35 H8.65)

He doesn’t run kalk
Doesn’t open windows
And skimmer is off most of the day (to control nutrients)
His at home co2 is through the roof and he’s borderline 8.7 keep in mind I took the same step with his as I did with mine. Rechecked calibration fluid and tested with kalk. But it’s still super high. We can figure it out and he also has the Neptune. We both gave up and are getting new probes lol

Calibration solutions can also be off. The pH 10 solution can drift down as CO2 enters it, which leads to measurements reading too high.

 

[jaime31]

Calibration solutions can also be off. The pH 10 solution can drift down as CO2 enters it, which leads to measurements reading too high.

Yeah that’s also a suspicion that I had. Thanks Randy for your input. I got the new probe coming in tomorrow I will give you guys an update