pH meter storage solution drying out and turning white?

[MagicMatt]

I have a Hanna pHep pH meter, and bought storage solution from them (along with cleaning solution and buffer solutions).

After every use I pour several drops of the storage solution into the well in the cap and close tightly on the meter. The next time I go to use it, there is a dried white flaky substance that has leaked out of the cap a bit, and when removing the cap it is all over the inside as well. I am assuming this is the storage solution.

So why is this happening? I would think the solution should remain liquid since the electrode should be kept moist. Any help is appreciated!

 

[Gavin C]

I have a Hanna pHep pH meter, and bought storage solution from them (along with cleaning solution and buffer solutions).

After every use I pour several drops of the storage solution into the well in the cap and close tightly on the meter. The next time I go to use it, there is a dried white flaky substance that has leaked out of the cap a bit, and when removing the cap it is all over the inside as well. I am assuming this is the storage solution.

So why is this happening? I would think the solution should remain liquid since the electrode should be kept moist. Any help is appreciated!

As the storage solution is saturated potassium chloride i believe.

Over time, if any evaporation of the solution occurs or I guess if any cooling of the solution occurs, KCL will crystalize and grow out from the cap and the device interface.

That would be my guess.

 

[day_trippr]

fwiw, my experience with a 98128 (pHep5) over few years is this happens all the time but has not had any apparent effects on the meter.
I try to refresh the storage cap monthly or when I pull it out for use so I catch it still "moist" but I do miss on occasion and that's when I'm greeted by the dried up white stuff...

Cheers!

 

[mabrungard]

Yep. Solution wicks up the sides and then evaporates which leaves the mostly KCl solids.

 

[MagicMatt]

Thanks for the replies guys. So I guess a follow up question is what can I do to prevent it, or is it a problem not worth worrying about?

 

[Gavin C]

Thanks for the replies guys. So I guess a follow up question is what can I do to prevent it, or is it a problem not worth worrying about?

I don't believe it's anything to be too worried about. The solution should still be saturated as your losing fluid and salts to the crystallization. The bulb is still immersed in a saturated KCl solution.

I could be 100% wrong though.

The mess would bug me enough to change out the fluid. Perhaps don't fill the cap quite so full. That could minimize this minor issue.

 

[Buckeye_Hydro]

Its not something to worry about - just assure that you always keep the sponge in the cap moist.

Russ

 

[MagicMatt]

Well that is what I'm worried about.....there is no sponge in the cap. There is just a little well of sorts that the actual probe goes into, and that's what I've been filling (with about 4 or 5 drops, which makes it full) of solution. When I cap it, I can only assume that the displacement caused by the probe pushes some (most?) of the solution into the rest of the cap.

But because of this, every single time I've opened the cap (even just a week later), it is bone dry inside. I'm following the instructions in terms of how to apply the storage solution, but this seems like a really ineffective method of keeping the probe wet.

What am I missing? Surely they didn't design this to have this shortcoming?

 

[Buckeye_Hydro]

Why not cut a small piece of foam for the cap?

 

[emsroth]

Bump

Any updates? New to pH myself and I have the same problem.

Was there any special cleaning required before using again? Hanna care guide says 30 minute soak in cleaning solution or an hour soak in storage solution to reactivate. Obviously I have a mash going right now.

 

[mabrungard]

If the probe was stored in storage solution and it dried out, the main problem is the loss of hydration. There isn't likely to be a need for 'cleaning solution' since that is intended for removing films and organics. The main fix for a dried out probe is to get it back into storage solution so that it can rehydrate and help restore the ionic balance for the salt bridge. It will take hours, if not days, for the probe to be restored.

As you may have already found, even with a cap on the probe, it can still eventually dry out. You either have to refresh the solution occassionally, or store the probe in a big bottle of solution. I just cut a hole in the cap of storage solution and inserted the probe into that bottle of solution.

 

[Rev2010]

I've found for pH meters that don't have a good rubber ring around the base to create a good seal that using a piece of tape wrapped fully around the area where the cap meets the body helps to seal in the moisture much better. Of course, always store it in upright standing orientation as well.


Rev.

 

[Mybuddypete]

Make sure to store your meter upright, don't store it laying on it's side.

 

[ScrewyBrewer]

I've eliminated the white crusties being formed by storing my pH meter in a small glass filled with storage solution. I then wrap plastic wrap around the meter and the glass holding it in place with two small elastic bands. The idea is to keep the storage solution sealed off from air and it works well.

 

[ScrewyBrewer]

Bump

Any updates? New to pH myself and I have the same problem.

Was there any special cleaning required before using again? Hanna care guide says 30 minute soak in cleaning solution or an hour soak in storage solution to reactivate. Obviously I have a mash going right now.

I've had my Hanna pH meter over four years now and have replaced the probe three times. Below are the steps I use, and Hanna item numbers, that keep a Ph meter in top working condition.

Soak probe in cleaning solution for an hour [HI7061]
Calibrate and take wort pH readings at 77F [HI7007-HI7004]
Soak probe in cleaning solution for an hour [HI70300]
Store Ph meter away with probe submerged in storage solution

...repeat the above steps as needed...

 

[ajdelange]

Thought I had responded here but guess not. KCl solution is one of two liquids (the other being He II) which exhibit "creep" i.e. the ability to climb the walls of a vessel containing them. Thus it isn't enough to seal in the usual sense. You must make sure the seal is a very good one. It is easy for the stuff to slip around the edges of the typical caps found on pH electrodes. The small bottles with a hole and o-ring in the caps are better but some will often still make it through.

In any case it's nothing to worry about. Just blast the crystals off with a squirt of DI water and replace the lost solution from time to time.

 

[tdibratt]

i have the same problem. I fill the cap (no sponge in it) and within 2 weeks I go check it's bone dry and white. What a poor design

 

[ScrewyBrewer]

i have the same problem. I fill the cap (no sponge in it) and within 2 weeks I go check it's bone dry and white. What a poor design

I put a few ounces of storage solution in a small glass and put my pH meter in it. Then I wrap plastic wrap around the meter and glass to seal in the solution and prevent it from evaporating. Using two small elastic bands to hold everything in place. That will prevent the meter bulb from drying out even after months of storage.

 

[Dustin_J]

I just cut a hole in the cap of storage solution and inserted the probe into that bottle of solution.

Same here, I hate those little caps - this is 100x easier and works much better.

 

[Unicorn_Platypus]

If the probe was stored in storage solution and it dried out, the main problem is the loss of hydration. There isn't likely to be a need for 'cleaning solution' since that is intended for removing films and organics. The main fix for a dried out probe is to get it back into storage solution so that it can rehydrate and help restore the ionic balance for the salt bridge. It will take hours, if not days, for the probe to be restored.

As you may have already found, even with a cap on the probe, it can still eventually dry out. You either have to refresh the solution occassionally, or store the probe in a big bottle of solution. I just cut a hole in the cap of storage solution and inserted the probe into that bottle of solution.

Hi Martin, I haven't brewed since prior to the pandemic (end of 2019) and my PH meter probe that was in storage has dried out. Should I assume its toast? Or do you think it could still be possible to rehydrate it?

https://aperainst.com/ph60-e-replacement-probe-for-ph60-pocket-ph-tester
The probes are about half the price of the meter, so would love to salvage it

Thanks!

 

[ScrewyBrewer]

Hi Martin, I haven't brewed since prior to the pandemic (end of 2019) and my PH meter probe that was in storage has dried out. Should I assume its toast? Or do you think it could still be possible to rehydrate it?

https://aperainst.com/ph60-e-replacement-probe-for-ph60-pocket-ph-tester
The probes are about half the price of the meter, so would love to salvage it

Thanks!

From my past experience, once the probe on a Hanna meter dries out, it needs to be replaced.

 

[mabrungard]

From my past experience, once the probe on a Hanna meter dries out, it needs to be replaced.

I agree. That drying also acts on the internal chemistry within the bulb and it's probably toast.

I strongly recommend avoiding 'all-in-one' pH meters like the PH60 since you're stuck with buying an overpriced, proprietary replacement part. Use a meter that has a BNC style, cable-mounted probe in order to get modestly-priced replacement probes.

 

[day_trippr]

The PH60-E replacement sensor assembly for my Apera ph60 meter costs $43.
The SE220 replacement sensor assembly for an MW-101 or MW-102 costs $46.

fwiw, I've had the Apera for four years now, and aside from murdering the glass bulb on the original sensor just two months in, the meter with the replacement sensor still works fine...

Cheers!

 

[Unicorn_Platypus]

Gonna suck it up and buy a replacement probe, thanks guys!