# low-cost pH meter maintenance?



## fafrd (Mar 25, 2017)

I've picked up one of the low-cost pH meters from Amazon and been pretty happy with it: https://www.amazon.com/dp/B01GO2QKVK/?tag=skimlinks_replacement-20

Aside from calibrating it with the included reference liquids, I've done nothing special for maintainance - rinse it, dry it, put the cap on it (dry) and put it away until next time...

I've seen a few winemakers now who have older and/or higher-end pH meters that require the sensing tip to be stored in liquid.

Is there some fundamentally new technology being used in this new crop of low-cost pH meters that avoids to complexity of this maintainance/wet-storage?

I know a fancier, more expensive pH meter may be more accurate, but my question is whether these low-end meters are truly as maintainance-free as they seem or if my instruction manual was missing a couple pages?


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## ibglowin (Mar 25, 2017)

Storing a pH probe in a storage solution is the best practice way to protect the probe and your investment. If you spend $15 for a pH meter you don't have much invested really. So your call at this point.


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## fafrd (Mar 26, 2017)

ibglowin said:


> Storing a pH probe in a storage solution is the best practice way to protect the probe and your investment. If you spend $15 for a pH meter you don't have much invested really. So your call at this point.



There is a black cap that could he filled with fluid, I suppose, but the instructions included absolutely no mention of this.

What 'storage solution' woukd I use?

Are these new low-cost meters based on the same technology as the older/higher-cost pH meters or is it possible they are based on some new technology that does not require moist storage!


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## DiscoStu (Mar 26, 2017)

I also have a 15$ meter from Amazon. Might be the same one, mines orange though. Storing it in liquid prevents the probe from drying out. If you use it often. Once a month. You should be fine. You don't need to dry the probe though. Just rinse with distilled water and shake it dry.


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## ibglowin (Mar 26, 2017)

You would use pH meter "Storage Solution" also available at Amazon

The cheap meters use the same technology (glass tipped Probe) they just use a very cheap version of the probe and very cheap electronics. Have no temperature compensation and are only 0.1 pH units accurate (at best).



fafrd said:


> There is a black cap that could he filled with fluid, I suppose, but the instructions included absolutely no mention of this.
> 
> What 'storage solution' woukd I use?
> 
> Are these new low-cost meters based on the same technology as the older/higher-cost pH meters or is it possible they are based on some new technology that does not require moist storage!


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## fafrd (Mar 26, 2017)

DiscoStu said:


> I also have a 15$ meter from Amazon. Might be the same one, mines orange though. Storing it in liquid prevents the probe from drying out. If you use it often. Once a month. You should be fine. You don't need to dry the probe though. Just rinse with distilled water and shake it dry.



Mine is branded 'ZACRO' and is blue.

The black plastic cap contains no round resevoir like the other one I saw, so what do you do, just fill the black cap half-full of storage solution and leave it at that?

Takng a reading every month or even two weeks seems a lot essier...


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## fafrd (Mar 26, 2017)

ibglowin said:


> You would use pH meter "Storage Solution" also available at Amazon
> 
> The cheap meters use the same technology (glass tipped Probe) they just use a very cheap version of the probe and very cheap electronics. Have no temperature compensation and are only 0.1 pH units accurate (at best).



Yeah, I'd seen that, thanks.

I read that the cheap meters have a thicker glass 'membrane' protecting/surrounding the electrode (which results in reduced sensitivity).

So unclear whether that thicker glass also prevents 'drying out' snce the directions make no mention of storing in solution'

Also, with no designed-in resevoir on the cap, I'd be worried that just putting liquid in there might result in a bubble against the electrode. I suppose it could be stored cap-up but then it might leak.

The cheapo pH meter I got is supposed to be temperature-compensated, but talk is cheap and I don't know how to verify...


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## kevinlfifer (Mar 27, 2017)

I store mine vertically with distilled water in the cap. I rinse and then calibrate with the buffer solutions. I keep the buffer solutions tightly sealed. Works fine.

I'm sure it is not as accurate has the units I used when I was in the research lab at Materion, but +/- .05-.1pH for wine ought to be close enough.


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## ibglowin (Mar 27, 2017)

That is actually the worst thing you could do to your pH meter! This is from the Hanna Website





kevinlfifer said:


> I store mine vertically with distilled water in the cap. I rinse and then calibrate with the buffer solutions. I keep the buffer solutions tightly sealed. Works fine.
> 
> I'm sure it is not as accurate has the units I used when I was in the research lab at Materion, but +/- .05-.1pH for wine ought to be close enough.


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## fafrd (Mar 27, 2017)

kevinlfifer said:


> I store mine vertically with distilled water in the cap. I rinse and then calibrate with the buffer solutions. I keep the buffer solutions tightly sealed. Works fine.
> 
> I'm sure it is not as accurate has the units I used when I was in the research lab at Materion, but +/- .05-.1pH for wine ought to be close enough.



I guess with just simple distilled water, even if there is an overflow it's no big deal.

What is special about the 'storage solution' that is supposed to make it better than distilled water?

And I agree, 0.1 precision should be sufficient for winemaking.

At crush, the main focus is on TA, but pH needs to be accurate to assure pH is in line, so a calibration makes sense.

Post-MLF, pH will drive sulfite levels but should be relatively stable, so at most one more calibration should be needed (to get an accurate read on post-MLF pH) as you are only monitoring stability through maturation. Of course, if you read any significant change in pH, calibrate to confirm before reacting.

I don't have any bottled buffer solution yet, only the few packs that came bundled with my meter - what is the shelf life of the bottled buffer solution?


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## ibglowin (Mar 27, 2017)

Please see the link and pic I posted above.



fafrd said:


> What is special about the 'storage solution' that is supposed to make it better than distilled water?


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## jburtner (Mar 27, 2017)

Some of the electrodes also let you replace the internal solution as a maintenance practice so that as the part ages it is able to be kept within certain tolerances.

Cheers!
-johann


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## fafrd (Mar 27, 2017)

ibglowin said:


> Please see the link and pic I posted above.



I'd missed your post because I guess our respective responses crossed in the ether .

Very helpful - thanks. So store dry and take the chance of eventually having to replace a $15 instrument, or store in proper storage solution (or 4.0 pH buffer solution in a pinch). Storing in distilled water is the worst of all options.

Is there any easy way to tell when the tip has 'dried out' ?

Also, as far as keeping the tip moist through frequent usage, any opinion on what frequency is recommended /safe?

These low-cost meters are now so inexpensive that looking at them as a disposable resource to be replaced every vintage or as-needed seems like a viable option...


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## fafrd (Mar 27, 2017)

jburtner said:


> Some of the electrodes also let you replace the internal solution as a maintenance practice so that as the part ages it is able to be kept within certain tolerances.
> 
> Cheers!
> -johann



Not these $15 pH meters (or at least, not mine .

My instructions actually state:

"Digital pH meter Maintenance

Always replace protective cap after using the digital meter to keep electrode from drying out due to prolonged exposure to air, which leads to slow and/or unstable readings. If electrode has been dried out immerse in ino distilled water for 2-3 hours."


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## ibglowin (Mar 27, 2017)

I have had an $89 Hanna pHep5 for 7 years now. I always rinse well with distilled water after each use. Blot the tip with a kleenex and put the cap back on. When you go to use it just let it sit in the buffer for a minute or two and calibrate and use. Honestly if you start experiencing problems its more than likely not that you stored it dry, but more than likely the fact that its just a cheap meter.


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## fafrd (Mar 28, 2017)

ibglowin said:


> I have had an $89 Hanna pHep5 for 7 years now. I always rinse well with distilled water after each use. Blot the tip with a kleenex and *put the cap back on. *When you go to use it just *let it sit in the buffer for a minute or two and calibrate* and use. Honestly if you start experiencing problems its more than likely not that you stored it dry, but more than likely the fact that its just a cheap meter.



Well when this ultra-cheapo meter craps out on me, I'll probably invest in a better piece of equipment closer to what you have next time.

Just to be clear, when you 'put the cap back on' is that an empty cap or a cap full of buffer / storage solution?

And when you 'let it sit in the buffer for a minute or two and calibrate' is that still sitting with the cap on in the buffer / storage solution or are you removing the cap and immersing the tip in a beaker-full of calibration solution?


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## ibglowin (Mar 28, 2017)

I store dry with cap on, no issues. You can also store with cap on with small drop of storage or 4 buffer solution. Either way works.

When you take your meter out for use you have to remove the cap and fill a small container with enough buffer solution to cover the probe and let it equilibrate for a minute or two.




fafrd said:


> Well when this ultra-cheapo meter craps out on me, I'll probably invest in a better piece of equipment closer to what you have next time.
> 
> Just to be clear, when you 'put the cap back on' is that an empty cap or a cap full of buffer / storage solution?
> 
> And when you 'let it sit in the buffer for a minute or two and calibrate' is that still sitting with the cap on in the buffer / storage solution or are you removing the cap and immersing the tip in a beaker-full of calibration solution?


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