Consistency Deficiency

[_Maq_]

@_Maq_ you said the NaOH has been deactivated. Are you 100% sure?

If we take for given that the alkalinity of your water is 3.00 °dKH, then such a water fully degassed would be over 9 pH. In equilibrium with atmospheric content of CO2, roughly pH = 8.3 to 8.6.
10.5 mg/L CO2 is required to make such water pH = 7.

 

[Hufsa]

If we take for given that the alkalinity of your water is 3.00 °dKH, then such a water fully degassed would be over 9 pH. In equilibrium with atmospheric content of CO2, roughly pH = 8.3 to 8.6.
10.5 mg/L CO2 is required to make such water pH = 7.

Do you have a link to where I can see the different levels?

 

[_Maq_]

Unfortunately, this is a Czech version. See the "Tillmans" page.

 

[Hufsa]

Do you know what the conductivity of the water is? If it is really low (less than ~50 microS (30 ppm "TDS")) then the pH will just be a movable feast. You could add a <"neutral salt"> (NaCl or similar) to raise the conductivity, but I just ignore pH in really soft water.

Straight tap water was like 54 "TDS" or something last I checked. But once ive prepared the water its closer to ~130 from Seachem Safe, GH and fertilizer combined. So I dont think the conductivity is too low then?

Theoretically it is pH 7, (equal numbers of H+ and OH- ions from the <"self-ionization"> of water), but only if the water is degassed.

I guess im just struggling to know if/when it is fully degassed(?)
This monkey can go shake a jar outside and take a reading, but how does the monkey know if the air is what it is supposed to be 😵 Too many moving parts..

At 3 dKH you are pretty near the amount of carbonate hardness that will cause the pH to go to <"~pH 8, via the carbonate ~ CO2 equilibrium">. It maybe that the shaking incorporated enough <"extra oxygen to raise the pH">? and was the water <"much warmer than the air">?

Yes it was almost nighttime, so the air was very cold.
Temperature is also an issue? ☹️ Does the jar-monkey have to wait until Norway turns aquarium temperature? That will be many months 🙊

 

[dw1305]

Hi all,

Straight tap water was like 54 "TDS" or something last I checked. But once ive prepared the water its closer to ~130 from Seachem Safe, GH and fertilizer combined. So I dont think the conductivity is too low.

That should be enough ions to give you a value.

....I guess im just struggling to know if/when it is fully degassed(?)

Degassed in this context means not having any dissolved gases, so basically boiled and then placed in an air tight container.

.....Yes it was almost nighttime, so the air was very cold.
Temperature is also an issue? ☹️ Does the jar-monkey have to wait until Norway turns aquarium temperature? That will be many months 🙊

Because gases are more soluble at lower temperature you can dissolve more gas. This applies to both CO2 and O2.

Oxygen is much less soluble than CO2, so will take longer to come out of solution if you've supersaturated the water with vigorous shaking.

Cheers Darrel

 

[Hufsa]

Hm. So what exactly are the right conditions to put the aquarium water sample in, in order to get an accurate reading?
My main concern with just leaving it sitting out somewhere is higher than "standard" CO2 levels in the rooms.
There would be no way to know if it hit that ~3 ppm or whatever its supposed to have naturally? (without a certain someone shaking it)
And putting it outside means much lower temperatures. So what do I do?

 

[Hanuman]

Hm. So what exactly are the right conditions to put the aquarium water sample in, in order to get an accurate reading?
My main concern with just leaving it sitting out somewhere is higher than "standard" CO2 levels in the rooms.
There would be no way to know if it hit that ~3 ppm or whatever its supposed to have naturally? (without a certain someone shaking it)
And putting it outside means much lower temperatures. So what do I do?

You are over complicating this. Shake your jar. Leave it to stabilize a few hours and take a reading. Or leave the jar overnight next to the aquarium where conditions are the same than the aquarium and take a reading the next day. You can leave it 24h. That should be enough.

 

[Hufsa]

You are over complicating this. Shake your jar. Leave it to stabilize a few hours and take a reading. Or leave the jar overnight next to the aquarium where conditions are the same than the aquarium and take a reading the next day. You can leave it 24h. That should be enough.

Not shaking and just leaving it overnight gives a much lower reading though, which one is it in my case? 8.15 or 8.6?

 

[Hanuman]

Not shaking and just leaving it overnight gives a much lower reading though, which one is it in my case? 8.15 or 8.6?k

How long did you wait to test after shaking?

 

[Hufsa]

How long did you wait to test after shaking?

Think I gave it like 5-10 minutes? I can repeat the process and document it better because i cant remember much for the life of me

 

[Hanuman]

Think I gave it like 5-10 minutes? I can repeat the process and document it better because i cant remember much for the life of me

Hence the reason I said for you to wait a few hours after shaking it so that oxygen can also degas. You could also have mutiple samples.
1. One you shake and read a few moments later.
2. One you shake and leave to rest multiple hours.
3. One you shake and leave overnight.
4. One you just leave overnight.

Then make an average. And you will be good to go.

 

[Wookii]

You are over complicating this.

‘Tis but the nature of the @Hufsa ! 😆

Not shaking and just leaving it overnight gives a much lower reading though, which one is it in my case? 8.15 or 8.6?

Surely an untouched glass of tank water, left next to the tank, will have reached full equilibrium with the surrounding air after 48 hours, without question. That’s your base line, job done!

 

[Hufsa]

..This is what the probe thinks of my 7 buffer solution 😠
Frickin knew there was a ghost somewhere, things just didnt add up 😤

The question now is, how long has it been wrong, and how wrong has it been 🤬 And can I even fix it?

11.03.23 I pulled the pH pen out of storage.
I was not very happy to discover that something had grown inside the cap with the probe and KCL storage solution.
It looked all kinds of nasty 🤢

I made a mental note to ask about this on the forum, and then promptly forgot about it.
Can this gunk have damaged the probe? It was not dry.

I cleaned the probe carefully with water and a partial Q tip to get all the gunk dislodged. Then I (seemingly successfully) two point calibrated it using 7 and 4 buffers and all seemed well.
I strapped it to the tank "poor man's ph meter style" and started taking measurements over the following days.
(old picture)

I never got any feedback on whether the ph pen could be kept like this with the probe into the tank for some days at a time, but it made taking a ph profile so much easier so I continued.
Since the probe is sitting in the tank water the reading stabilizes almost instantly.
Can using it like this have damaged the probe? Or could micro CO2 bubbles touching the probe have damaged it?
Is there a physical difference between a probe thats made to sit continuously in the water and one thats meant for taking momentary readings?

Then followed some days of confusingly high ph profiles, and strange day to day variations. I dont know how much of this is the reality of the tank and how much of this is from the haunted probe.
I think a fair bit of it is the tank, because it looks like a disaster zone in there at the moment, and I dont think it would look like that if all was merry and well.

That brings us to today, I was going to recalibrate the pen, and it wouldnt recognize the 7 buffer. The auto calibration feature kept reading it as a 10 buffer no matter what I tried. I cleaned the sample cup again and rinsed it super well, and put in new 7 buffer. Nope, still auto switching to 10. Then I let the probe sit in some storage solution and then 4 buffer. Still wrong.
I cleared the incorrect calibration and set the pen back to standard / uncalibrated.
Still its reading 8.8 in the 7 buffer. I cant find any way to turn off the auto buffer recognition or to set 7 buffer manually.
Ive somehow managed to nudge it down to not reading the 7 buffer as 10 any more, so now it just sits pending for a while until declaring that something has gone wrong and exiting the calibration mode.
Im gonna leave it in the KCL storage solution for even longer and hope that it comes to its senses again.

What do you think, can I salvage it?
(Ya'll better not mention any expensive ph loggers unless also offering to pay for it in the same sentence )

CO2, why you gotta be so hard ugh

 

[_Maq_]

What do you think, can I salvage it?

Long ago, I've spent some money for "pH probe cleaning solution". It turned out to be very diluted sulfuric acid.

 

[Hufsa]

Long ago, I've spent some money for "pH probe cleaning solution". It turned out to be very diluted sulfuric acid.

Do I interpret this as a suggestion to clean the probe?

 

[Hanuman]

What do you think, can I salvage it?

If you have cleaned the pen and it is still not reading the right calibrating solution PH, the only thing that you could do at this stage that won break the bank is to buy a new PH calibrating solution to make sure it's not that. It could be that it is contaminated. But I'll be honest, I think the problem is the pen itself. How old is it? IME these pens don't last more than a year or 2 if used often and/or allowed to dry out. I have two of them right now. One is totally toast. The other one is on its way to heaven. Last time I try calibrating it, it would just error on me for 10 minutes, then suddenly worked. It also drifts very fast. I calibrate it each and every single time I use it. Pretty bothersome.
Looking at your pen it looks like it can be unscrewed from the bottom. This is very similar to mine where you can just unscrew it and just buy the sensor rather than the whole pen.

That is why I really don't want to spend any more money of PH pens but looking into a PH logger with a proper double junction probe.

 

[Hufsa]

If you have cleaned the pen and it is still not reading the right calibrating solution PH, the only thing that you could do at this stage that won break the bank is to buy a new PH calibrating solution to make sure it's not that. It could be that it is contaminated.

I still have left to clean the pen more aggressively I suppose, I just want to be sure im using the right stuff for cleaning it so I dont break it any further
Im pretty sure I have more acids and chemicals than the average person, but I dont have sulfuric acid which Maq is suggesting 😏 (Note to self: Cannot have too much acid 👀)

But I'll be honest, I think the problem is the pen itself. How old is it?

The probe is labeled 22, I purchased it october last year so it should still be good unless I killed it with the gunk / untraditional usage.

Looking at your pen it looks like it can be unscrewed from the bottom. This is very similar to mine where you can just unscrew it and just buy the sensor rather than the whole pen.

Yeah I see they sell replacement probes, so if I cant get this one to come to its senses then I think ill try buying a new probe for the pen, it stings a little but at least it wont break the bank.

That is why I really don't want to spend any more money of PH pens but looking into a PH logger with a proper double junction probe.

What makes the difference in logger probes? How are they made so that they are not subject to the same issues?

 

[Hanuman]

I still have left to clean the pen more aggressively I suppose, I just want to be sure im using the right stuff for cleaning it so I dont break it any further
Im pretty sure I have more acids and chemicals than the average person, but I dont have sulfuric acid which Maq is suggesting 😏 (Note to self: Cannot have too much acid 👀)

No need for sulfuric acid if you don’t have some. You could use vinegar that would probably be enough to remove any scale build up on the reference probe (metallic probe). The glass electrode should be pretty easy to clean with water and a q-tip/paper. Just dip the pen probe in vinegar for 15-20 minutes then rinse with water. Then calibrate.

The probe is labeled 22, I purchased it october last year so it should still be good unless I killed it with the gunk / untraditional usage.

It's not that old indeed so I doubt that using it that way killed it. It's just the nature of these PH pens. They drift all the time. It's painful.

What makes the difference in logger probes? How are they made so that they are not subject to the same issues?

It's not the logger per say that is different, it's the probe. Being a double junction probe makes them more reliable and they are usually designed to be kept permanently in the liquid you are measuring. You don't technically need a logger, that's just a fancy feature added to some products. You could just buy the double junction probe and the monitor that will read the PH when you turn it on. They also usually come with a temperature probe for temperature compensation.

This is what a double junction probe looks like:


And this is a probe with a reader/monitor. Even cheap ones will be more accurate and stable than traditional PH pens. They also require less calibrating than PH pens.

 

[_Maq_]

it stings a little but at least it wont break the bank.

What about this ? Is it that expensive? I think reliable pH meter is a necessity.

 

[Marios]

Hi Hufsa,

I am currently using the same ph pen and had a similar problem with it. Its reading was drifting and wasn't giving me a stable, or correct reading and when I tried calibrating it, it would not recognize the solutions. I tried cleaning it with HCL and vinegar and I've even purchased new calibration solutions, but still the problem persisted, so ended up replacing the electrode and is now working fine. I think I paid something like eur 25 including shipping.

Here is the link from the website that I've made the purchase if you are interested.

Sonda / Electrodo de repuesto pH para Medidor Adwa AD11 / AD12 (AD11P)

Sonda pH compatible con los medidores Adwa AD11/AD12 El electrodo de pH es un sensor basado en una celda electroquímica. Esta celda comienza a sufrir desgaste desde el momento de su fabricación hasta el final de su v

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