Apera SX610 pH tester

[hlmbrwng]

I did a forum search and didn't find anything. Does anyone have experience with this tester?

This one has a single point calibration at 7.0. The Apera pH60 has a three-point calibration. It's nice that there is only one calibration pH needed, but I imagine the calibration is not as effective. I.e., the reading will not be as accurate the further away from 7 you go. Is it correct to think this? It would be nice to only need to purchase 1 calibration solution/powder.

If anyone has used this, does it seem reliable?

 

[hlmbrwng]

Ah, I just noticed that the accuracy of the sx610 is +-0.1, while the accuracies of both the pH60 and sx620 are +-0.01

 

[ajdelange]

You are correct in your assumption that a two point calibration is necessary for accurate pH readings.

 

[Vale71]

And display resolution is not the same as accuracy. Being able to display values with 0.01 resolution doesn't mean that it's necessarily more accurate. Accuracies better than 0.05 in a PH meter are very hard to achieve as calibration has a really huge impact on accuracy at such levels.

 

[ScrewyBrewer]

The difference is with .1 resolution the pH value can range between .06 and .14. I went with .01 resolution and 3 point calibration. For brewing, I use 2 point calibration using 4.01 and 7.01 solutions since they are more aligned to brewing pH measurements.

 

[hlmbrwng]

I have never struggled so much deciding on a piece of equipment for brewing. I have spent the past 3 days looking at the pros and cons of different pH meters and have not settled on one. Although expensive, the cost of my time is adding up to be much more than the meters themselves! I guess I just need to pull the trigger and buy one of these.

The importance of the pH of the mash has been stressed here and elsewhere, and I do understand the importance. The issue is that a pH meter is an expensive piece of equipment that doesn't last very long, even if it is well taken care of. The manufacturers' web sites say that the probes will last 1-2 years IF stored properly! And the probes cost almost as much as the entire brand-new device. Oh yeah, then there is the calibration solution. Okay, okay. I'll stop. I know I'm not the only one with these woes.

I keep purchasing these cheap ones that break quickly and that do not have very good accuracy, so I am throwing money away there. Which is why I want to upgrade. I guess if I'm going to be serious about my brewing water, it's just a yearly expense that I need to accept.

I think I'm going to go with the either the Apera sx610 or ph60.

 

[Vale71]

The difference is with .1 resolution the pH value can range between .06 and .14. I went with .01 resolution and 3 point calibration. For brewing, I use 2 point calibration using 4.01 and 7.01 solutions since they are more aligned to brewing pH measurements.

And if the second PH meter had 0.2 (not saying it does, just hypothetically) accuracy the real value could still be between +0.2 and -0.2 of what is displayed, even with 0.01 resolution. In the end, you just paid more to measure noise more accurately.

 

[hlmbrwng]

I decided on the Apera ph60. I'll report back after I've used it for some time.

 

[ScrewyBrewer]

And if the second PH meter had 0.2 (not saying it does, just hypothetically) accuracy the real value could still be between +0.2 and -0.2 of what is displayed, even with 0.01 resolution. In the end, you just paid more to measure noise more accurately.

I really have no other agenda here. At the end of the day, it's all a matter of what you like and what you can afford.

 

[Vale71]

Neither do I. I was just pointing out the fallacy of mixing up display resolution with precision, something that is often exploited by unscrupolous manufacturers to make their gear look better than it is.
If my post offended you in any way it must be some kind of misunderstanding.

 

[pompeiisneaks]

This is an area I've been researching lately as well. What about the Hannah phep+ it has .01 ph resolution, and accuracy of .1, and two point calibration. https://hannainst.com/hi98108-phep-ph-tester.html

 

[hlmbrwng]

This is an area I've been researching lately as well. What about the Hannah phep+ it has .01 ph resolution, and accuracy of .1, and two point calibration. https://hannainst.com/hi98108-phep-ph-tester.html

I think for the reasons mentioned by Vale71 and ScrewyBrewer, maybe not the best option considering the accuracy. I went with the ph60 because it has +-0.01 accuracy (not just resolution), and the probe can be replaced for about $30 bucks.

With the Hanna pHep+, if you, for example, have a reading of 5.5 pH, it could really be anywhere from 5.4 to 5.6, assuming that the device is holding its calibration well.

 

[pompeiisneaks]

Excellent, was somewhat wondering that myself. So either the one you recommend, or if going hannah, they have this: https://hannainst.com/hi98128-phep-ph-tester.html. It seems the apera is a bit less expensive, are they generally considered better than hannah, or same ballpark quality etc?

 

[ScrewyBrewer]

Neither do I. I was just pointing out the fallacy of mixing up display resolution with precision, something that is often exploited by unscrupolous manufacturers to make their gear look better than it is.
If my post offended you in any way it must be some kind of misunderstanding.

I see what you're saying. My meter has a pH accuracy of .05 and a resolution of .01 and it cost $179. I see benchtop meters in the $400 range with a pH accuracy of .01 and a resolution of .01 which is a little out of reach for me. But I still favor the .01 resolution over meters with .1 pH resolution for some reason.

 

[ScrewyBrewer]

I think for the reasons mentioned by Vale71 and ScrewyBrewer, maybe not the best option considering the accuracy. I went with the ph60 because it has +-0.01 accuracy (not just resolution), and the probe can be replaced for about $30 bucks.

With the Hanna pHep+, if you, for example, have a reading of 5.5 pH, it could really be anywhere from 5.4 to 5.6, assuming that the device is holding its calibration well.

Unless I'm mistaken that meter displays pH at a 0.01 pH resolution but with an accuracy of ±0.10 pH which is not quite the same thing.

 

[pompeiisneaks]

Unless I'm mistaken that meter displays pH at a 0.01 pH resolution but with an accuracy of ±0.10 pH which is not quite the same thing.

Isn't that the exact same thing that @hlmbrwng just said?

 

[Vale71]

But I still favor the .01 resolution over meters with .1 pH resolution for some reason.

I think it's just human nature.
It's like buying portable computers with extremely high resolution but too small a screen area. The pixel density is so high that your eye can't see all the detail, but it felt really good buying it anyway.

 

[ajdelange]

And if the second PH meter had 0.2 (not saying it does, just hypothetically) accuracy the real value could still be between +0.2 and -0.2 of what is displayed, even with 0.01 resolution. In the end, you just paid more to measure noise more accurately.

That's not what accuracy means here. The specified accuracy is the rms error seen in a series of measurements of a buffer over some period of time post calibration. At calibration the error is 0. The meter will calculate the slope and offset necessary to make the meter read whatever pH you told it the buffers delivered. Over time the electrode will drift and produce different voltages in those same buffers such that the readings will change until the meter is recalibrated. Thus accuracy for a pH meter is a measure of electrode stability. This assumes that the meter itself is designed such that its self noise in both the voltmeter and temperature sensor channels map to pH dither appreciably less than that caused by drift.

Thus, roughly speaking, accuracy of ±0.2 pH means that out of a large number of readings taken in the specified time period (the only instance in which I have ever seen that given was for the Hach pH Pro for which it is 1 hour) 68% of them will be within 0.2 of the true pH, 95.5% of them will be between 0.4 of the true answer and 99.7% of them will be within 0.6 pH of the true answer. This is why it is important to have a good accuracy (stability) spec. A reading from a meter with specified accuracy of 0.01 has a 99.7% chance of being within 0.03 pH of the "correct" answer and a 95.5% chance of being within ±0.02. That's the kind of odds that give me some comfort. Note that "correct" is in quotes. That's because "correct" here means whatever the buffer pH is which is not what its label says but rather close to that with the rms error typically ± 0.02 pH (0.01 tolerance buffers are also sold at higher price). This, in the same fashion as the meter accuracy spec, implies that 68% of the bottles of buffer labeled 4.01 ± 0.02 pH leave the factory with 3.99 < pH < 4.03 but that 4.5% of them have pH < 3.97 or pH ≥ 4.05. Meter error of ± 0.01 and buffer error of ± 0.02 combine (rss) to give and overall error of ± 0.0223. Thus the overall accuracy of the of the calibrated meter is dominated by the accuracy of the buffer. This is a mark of a good meter which we define as being one that allows us to be limited in accuracy by the thing over which we have not control: buffer accuracy. It adds insignificant error 10%) to the overall error and we wind up 99.5% confident that a reading from a meter that meets its spec of ±0.01 calibrated with a NIST traceable 0.02 buffer is within a band ± 0.046 of the true pH of the solution being measured.

As to precision we note that 0.01 precision contributes "quantizing noise" at the display of ±0.003 pH, well below the 0.02 error attributable to the buffer and thus its contribution to the overall error is insignificant. For precision of 0.1 the quantizing noise is 0.03 pH which will dominate the buffer error and thus a meter with that level of precision is not a good meter.

To the OP: We advise here using one of the three meters that has been vetted here these being the Hach pH Pro Plus, the Milwaukee MW101 and the Omega pen style meter whose number I can never remember. By vetted we mean that several samples of the meter have been checked to see that they meet the stability specification for at leas an hour (see Sticky). This is not to say that the meter you are considering won't pass the stability test. It well may and if several pioneers want to try it to see if it does, it can potentially be added to the list.

 

[ScrewyBrewer]

Thank AJ you for sharing how to fully interpret the accuracy specifications when shopping for a pH meter.

 

[Labrat]

Is there any update on the Apera PH60?