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Ph Pen storage ?

eminor

Member
Joined
5 Feb 2021
Messages
784
Location
France
Hello, i bought a ph pen years ago, i used distilled water to calibrate and to store it, it lasted few weeks...

I have a new one, does i need distilled water with calibration powder or can i use RO water ?

I've read that KCL is needed for storage, i don't have any is there any other option ? thx
 
Most manufacturers say it's acceptable to use pH 4 buffer as a backup if you don't have saturated KCl.
Thanks, does i need distilled water for ph4 buffer or can i use RO to make it?
 
It likely doesn't matter, but if you're concerned that your RO isn't clean enough, it doesn't hurt to use distilled. You don't need very much.
 
It likely doesn't matter, but if you're concerned that your RO isn't clean enough, it doesn't hurt to use distilled. You don't need very much.
I think osmosis water is good because it is a filter that is larger than my house, the water is used to dye clothes in a factory, I take the water just before they add stuff, there is a lab in the factory, the filters are necessarily changed when necessary, i once had distilled water from there, the water was blue, they need less than 30min to make 20 liters !!!

the Ro water flow is crazy fast =)
 
Thanks, does i need distilled water for ph4 buffer or can i use RO to make it?
I wouldn’t think it matters if you’re using it to mix solution for storage and not calibration. Probe storage solution is pretty cheap though and with most probed you are only using a drop or two in the cap each time.
 
Hi all,
Most manufacturers say it's acceptable to use pH 4 buffer as a backup
Useful to know.
i don't have any is there any other option ?
Could you get it as "sodium free salt?". If it has some impurities it wouldn't matter for this usage, so even "low sodium salt" should do.
Probe storage solution is pretty cheap though and with most probed you are only using a drop or two in the cap each time.
True.

cheers Darrel
 
Hi all,

Useful to know.

Could you get it as "sodium free salt?". If it has some impurities it wouldn't matter for this usage, so even "low sodium salt" should do.

True.

cheers Darrel
Yes i can buy sodium free salt
 
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Hi all,

That is perfect, and should be pure (or pure enough for this use), KCl.

cheers Darrel
I found medication with pure KCL, does i need a special amount of KCL or can i just mix RO water with KCL ? thx
 
For probes from a pH controller, that live in the tank full time, would it be beneficial to buy a second probe and swap them out at intervals? Letting the probe that is not in use soak for that interval in 3M KCl?
 
Is that normal the powder is hard to mix with water ?

i added 44.8g of KCL in 20cl water, might be the problem ? can't add much more because don't have enough KCL
 
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Hi all,
For probes from a pH controller, that live in the tank full time,
It would depend on <"how they work">, you can potentially get<"solid state pH probes">, but they are quite expensive.
You also need an ISFET probe where it uses a "reference field effect transistor" (REFET), rather than a silver chloride (AgCl) glass reference electrode.
If you look at the manufacturers instructions you may find that the probes are meant to be replaced (and discarded) on a "6 month" or similar schedule. Personally I would be reluctant to trust the value shown on the meter, without independent verification from a calibrated, buffered pH meter.

cheers Darrel
 
Hi all,

It would depend on <"how they work">, you can potentially get<"solid state pH probes">, but they are quite expensive.

If you look at the manufacturers instructions you may find that the probes are meant to be replaced (and discarded) on a "6 month" or similar schedule. Personally I would be reluctant to trust the value shown on the meter, without independent verification from a calibrated, buffered pH meter.

cheers Darrel
Thanks Darrel, the probe is just a standard type with the membrane/liquid. I do confirm it with a Hanna pH pen.
I was just thinking if I rotated between 2 probes, while having the out of use probe soak in storage solution it may extend the life by ‘recharging’ the fluid inside.
 
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