[xchcui]

Hi.

I have a cheap pen digital pH meter and i would like
to know how to store it.The instructions in its manual
are not clear and minimal.
I know that in general glass electrode should be store in storage solution and there are pen type ph meterthat have some kind of sponge inside their cap so you can drip some drops of storage solution inside the cap.But this type of cap has nothing inside and the manual doesn't mention any storage solution.It says only to clean the electrodes with distilled water,wipe it dry with filter paper and return the cap.After that it has a warning not to forget to return the cap so the electrode won't dry.I guess that this specific ph meter was not made to be in storage solution,but after i make the cleaning with distilled water,should i leave the glass electrode and the diaphragm of the reference electrode(see photo blue arroy)slightly wet before i return the cap or should i dry completely the diaphragm
and the glass electrode?
The link of the photo is:
https://bit.ly/2EvZlkH

Thanks.

[a10t2]

You *must* store the probe in liquid, preferably KCl storage solution. Just pour a few mL into the cap before you put the meter away.

[Bob357]

+1
I might also add that even though it is supposed to have ATC, testing samples at higher temperatures quickly degrades the probe. For the price of that meter I doubt it will last long anyway, but cooling samples to room temperature will maximize its life.

[KellerBrauer]

+1
...but cooling samples to room temperature will maximize its life.

+1
It will also give the most accurate readings.

[goose]

Definitely store the probe in a pH Meter storage solution, Potassium Chloride (KCl).  If the glass electrode dries out it will take several hours of storing it in a liquid to obtain accurate readings.  The storage solution will also increase the useful life of the probe.

The storage solution is pretty cheap and should be available at your LHBS.  If not the major online supply outlets will have it.

Also as Bob357 says, take your readings at as close to room temperature as possible to extend the life of the probe.  I never go about 80 degrees.

[denny]

+1
I might also add that even though it is supposed to have ATC, testing samples at higher temperatures quickly degrades the probe. For the price of that meter I doubt it will last long anyway, but cooling samples to room temperature will maximize its life.

ATC corrects for instrument temp, not sample temp

[Robert]

+1
I might also add that even though it is supposed to have ATC, testing samples at higher temperatures quickly degrades the probe. For the price of that meter I doubt it will last long anyway, but cooling samples to room temperature will maximize its life.

ATC corrects for instrument temp, not sample temp

And actually is intended just to correct for temperature of the instrument when calibrating, so you don't have to manually calibrate.

[xchcui]

Thanks for your replies.
In general pH-meter glass electrode must to be immerse in storage solution,indeed,but in this specific ph meter,i am 100% sure that it was made to be store without storage solution.The protective cup doesn't have any special place inside it to drip some storage solution and the manual guide doesn't mention anything about that.
The manual guide is not clear enough,but i believe that if the glass probe had need to be stored in a storage solution,which it is a very important information,the manual would have mention something about that.
Lets assume that it doesn't need storage solution,
Is it okay,after cleaning with distilled water,to leave the glass electrode and the diaphragm of the reference electrode wet(leftover distilled water)before i return the cap?or i better dry them with paper filter as the manual adviced?Is it matter if the diaphragm of the reference electrode be dried?

[goose]

Thanks for your replies.
In general pH-meter glass electrode must to be immerse in storage solution,indeed,but in this specific ph meter,i am 100% sure that it was made to be store without storage solution.The protective cup doesn't have any special place inside it to drip some storage solution and the manual guide doesn't mention anything about that.
The manual guide is not clear enough,but i believe that if the glass probe had need to be stored in a storage solution,which it is a very important information,the manual would have mention something about that.
Lets assume that it doesn't need storage solution,
Is it okay,after cleaning with distilled water,to leave the glass electrode and the diaphragm of the reference electrode wet(leftover distilled water)before i return the cap?or i better dry them with paper filter as the manual adviced?Is it matter if the diaphragm of the reference electrode be dried?

The instructionsfor my Milwaukee pH meter and the one for the Hanna hand held meter I have as a backup recommend not to use distilled water for storing the probe.  According to the instructions distilled water can reduce the useful life of the probe.

[Robert]

Yes, the correct storage of the probe is in a saturated potassium chloride solution, because this is the same as the reference solution inside the bulb.  Equilibrium must be maintained or the probe will not function correctly.  If not stored this way, it must be reconditioned by 2-24 hours immersion in KCl solution, followed by recalibration, before use, and it may be irreparably compromised.  Chemistry nerds can elaborate on this, but it appears that the cheap meter came with a very incomplete set of instructions, as all pH meters will have the same fundamental requirements.  One could spend a lot of time and money trying to salvage a bargain instrument, only to have it never perform properly, thereby leading to undesirable results in many batches of beer.  Perhaps a small upfront investment in a decent meter and learning its proper use would be worthwhile.

[xchcui]

Storing the ph meter in distilled water,as goose mentioned,will reduce the ph meter life indeed.
But it wasn't my intention.I refer to the leftover distilled water.I meant to ask:after i clean the electrodes with distilled water(and give it a good shake)what is better,to wipe the glass electrode and the diaphragm completely dry and recap the ph meter or leave the leftover of distilled water on the glass electrode and the diaphragm before recap?I would like to mention,again,that this pH meter is not meant to be in storage solution(even though it should have the same fundamental requirements as other pH meter).So i would like to focus on those two options:wipe it dry(glass electrode and diaphragm) before recap or shaking the ph meter after cleaning with distilled water and return the cap while there are some leftover distilled water on the glass and the diaphragm.
What is better(or less bad)between the two options?and why?

[a10t2]

What is better(or less bad)between the two options?

Those two options are equally bad.

and why?

Because the probe should be kept in storage solution.

[Robert]

Because the probe should be kept in storage solution.

And never touched directly with anything.

[xchcui]

What is better(or less bad)between the two options?

Those two options are equally bad.

and why?

Because the probe should be kept in storage solution.

I know why keeping the glass electrode dry is not good,but how may leftover distilled water on the glass probe and on the diaphragm may chemically affect them?
I would like to mentioned,again,that they are not stored in distilled water,it is just leftover of distilled water.
And,again,this ph meter is not allowed to be kept in storage solution!!!
From your answers,i guess that you are not familiar with this type of ph meter and you don't have the knowledge to give me a reliable answer for that specific ph meter.
But thanks anyway for your replies:)