PH pen choosing help and questions

[Hufsa]

I was about to purchase a PH pen from Hanna, I thought I had the choice nailed down but suddenly now I am a bit confused.

The original option has:
pH Accuracy ±0.1 pH
pH Resolution 0.01 pH

While the slightly cheaper option has:
pH Accuracy ±0.1 pH
pH Resolution 0.1 pH

For the pH resolution of 0.01 pH to be useful, doesnt accuracy also have to be 0.01?
If the accuracy is the same on both meters, what is the point of the higher resolution readout?



The customer service rep is also trying to sell me a more expensive meter with a replaceable probe. Is a replaceable probe even needed for our aquarium use if the non replaceable is stored correctly?
The more expensive one has
pH Resolution 0.1 pH
pH Accuracy (@25°C) ±0.1 pH



I need buffer solution right, and it seems the bottles are good for 3-4 years after opening. 1 liter and 500ml cost almost exactly the same, so I was thinking to get 1 liter, might as well?
Do I also need storage solution or can I use one of the buffers?

Is there anything else I need other than the pen and the buffers, or am I good to go?
I would ask the rep but after they tried to upsell me a more expensive pen with the premise that it comes with buffer so "its better if you're only going to use it a few times", I dont trust them fully and would rather get advice from UKAPS

 

[Zeus.]

more expensive meter with a replaceable probe.

Handy as then you can just replace the probe and good as new.

Is a replaceable probe even needed for our aquarium use if the non replaceable is stored correctly?

'If' stored correctly should last many years

I need buffer solution right

you need the storage solution and buffers for calibration
I use the cheapo packages

They are not the correct pH as the Hanna ones are, but I feel they are close enough and all I am interested in is the pH change not the actual pH
I have a Hanna pH pen and I do find it a bit of a PITA to calibrate and new probes extensive. I do find my pH controller more handy with a BNC probe which is cheap to replace about £20 and dead easy to calibrate.
I feel I have no need to know the actual pH for my scapes ATM, the pH change is just a proxy to stable [CO2]

 

[Hufsa]

you need the storage solution

Is this solution just put into the pen or do I need some sort of special container to put the things in? If there is a DIY option I am very interested as the budget is tight

I do find my pH controller more handy with a BNC probe which is cheap to replace about £20 and dead easy to calibrate.

Which controller would this be?

I feel I have no need to know the actual pH for my scapes ATM, the pH change is just a proxy to stable [CO2]

Yeah I agree, I dont care what my ph is I just want to buy a good enough meter to tune in a stable CO2 level

Thanks for the help, do you have any thoughts about the accuracy thing?

 

[Hanuman]

@Zeus. < Poor man PH probe when you lose in crypto >

A PH probe/monitor is my next purchase. < Check this out >

@Hufsa I would be you, I would forget the PH pen. A PITA and they drift, no matter how expensive and fancy they are. Probes also drift but are considered more stable because they are continuously in a solution and they are double junction. I think PH pens are not double junction. This said probes also need calibration once in while too but as @Zeus. said what is important is the PH difference, not really the absolute number.

 

[Hufsa]

@Hanuman ive got hella BBA and GTA atm and have been religiously taught that the prime suspect is poor CO2.
So I just want some way of accurately doing a ph profile. Basically I just want to get rid of the algae.
Are you saying to go for a continous meter / probe instead?

 

[Hanuman]

@Hanuman ive got hella BBA and GTA atm and have been religiously taught that the prime suspect is poor CO2.
So I just want some way of accurately doing a ph profile. Basically I just want to get rid of the algae.
Are you saying to go for a continous meter / probe instead?

Yes. That's what @zeus also suggests. My experience with PH Pens (and I am already on the 2nd) is that they are painful. You test your water, you get a result. Test your water again 2 minutes later and the result is different. So you test again and again until you get a moreless average number. A pain. Now each time I make a test I calibrate the pen but still then it gives me some odd results at times. Lot's of waste of time for a so so reliability.

 

[john6]

Rather than buy the ph buffer sachets, why not buy the buffer solutions in bottles, works out alot cheaper.
You can buy 250ml of 4, 7, and 10 for under £4 each, even cheaper if you buy as a bundle.

 

[Hufsa]

You can buy 250ml of 4, 7, and 10 for under £4 each, even cheaper if you buy as a bundle.

Ah can you link me this?
I am located in Norway, so sometimes the options over here are much more expensive, especially shipping from abroad

Yes. That's what @zeus also suggests. My experience with PH Pens (and I am already on the 2nd) is that they are painful. You test your water, you get a result. Test your water again 2 minutes later and the result is different. So you test again and again until you get a moreless average number. A pain. Now each time I make a test I calibrate the pen but still then it gives me some odd results at times. Lot's of waste of time for a so so reliability.

Hmm I see. Do you have a continuous meter in mind?

 

[john6]

I buy from APC pure, not sure if they deliver to Norway but worth a look.
They are also on ebay and sometimes cheaper than their website.

 

[Hanuman]

Ah can you link me this?
I am located in Norway, so sometimes the options over here are much more expensive, especially shipping from abroad


Hmm I see. Do you have a continuous meter in mind?

See link I posted above. That's not technically aimed at aquriums but a ph probe is a PH probe. It stores the date in the cloud and you can see your profile. I am pondering buying one myself.

 

[john6]

Hmm I see. Do you have a continuous meter in mind?

I use the Aqua Medic Probe in my reef tank, its as accurate as it needs to be, i calibrate it every 6 months and holds its calibration very well.

 

[zozo]

It all depends on what the meter actually is used for, it can be used for a variety of mediums to measure its acidity. And the user manuals are a one size fits all scenario-based upon a worst-case scenario. For example, used in horticulture to measure fertilizer solutions that are highly concentrated (salty) and depending on the target crop that needs to be fertilized it can be rather acidic down to pH 5.0

The glass probe is a semi-permeable membrane (porous glass) and it contains a gelly reference solution with an electrode in it. The meter itself is a voltmeter and it measures the resistance difference between the reference solution and the medium solution. Therefore the probe should be semi-permeable since non-porous glass is an insulator.

The reference solution in the porous probe can get diluted/contaminated over time with the medium that is measured, or dry out if not stored correctly, rendering the meter useless and can no longer be properly calibrated. Depending on the quality of the membrane the lifespan can vary. If used extensively frequent also in relative aggressive mediums it will have a negative impact on the lifespan. Therefore meters with refillable or replaceable probes are on the market. Also, the refillable probes have an end of life they can get dirty and clog or wear out and get unreliable.

Since the manufacturer of the meter doesn't know what you are going to use the meter for it will always advise on the worst-case scenario regarding maintenance. And using it in a fish tank to measure a tad of fertilized tapwater is far from the worst-case scenario and it will wear out your meter much less...

That's about all I can say about it, can't tell you what to buy nowadays... The market is flushed and the outside of the device never shows the quality. I've used cheap meters that did it pretty good and used expensive ones that did a crapy job. After a while of playing with it, I became rather unsure if the importance of pH in a fish tank is worth investing money in to know it. IMHO it's not, but this is a personal decision you should make yourself... The opinions in this vary as much as the numbers of meters out there I guess...

 

[Hufsa]

See link I posted above.

cries in wallet

Are there some good options around the 50-75 euro range?
Even for the Hanna pens I was hoping to spend less.

I just want some stable CO2 my dudes 😅

 

[Zeus.]

Is this solution just put into the pen or do I need some sort of special container to put the things in? If there is a DIY option I am very interested as the budget is tight

you can put it in the pH pen lid, I do find getting the lid on/off a PITA also, then to leave it in tank 😬 I got the Hanna solution for storage - I should use it more

Which controller would this be?

One I got from CO2 ART- used as pH pen only ATM

@Hanuman ive got hella BBA and GTA atm and have been religiously taught that the prime suspect is poor CO2.
So I just want some way of accurately doing a ph profile. Basically I just want to get rid of the algae.
Are you saying to go for a continous meter / probe instead?

a pH logger would make doing a pH profile easy - even allowing for drift

It all depends on what the meter actually is used for, it can be used for a variety of mediums to measure its acidity. And the user manuals are a one size fits all scenario-based upon a worst-case scenario. For example, used in horticulture to measure fertilizer solutions that are highly concentrated (salty) and depending on the target crop that needs to be fertilized it can be rather acidic down to pH 5.0

The glass probe is a semi-permeable membrane (porous glass) and it contains a gelly reference solution with an electrode in it. The meter itself is a voltmeter and it measures the resistance difference between the reference solution and the medium solution. Therefore the probe should be semi-permeable since non-porous glass is an insulator.

The reference solution in the porous probe can get diluted/contaminated over time with the medium that is measured, rendering the meter useless and can no longer be properly calibrated. Depending on the quality of the membrane the lifespan can vary. If used extensively frequent also in relative aggressive mediums it will have a negative impact on the lifespan. Therefore meters with refillable or replaceable probes are on the market. Also, the refillable probes have an end of life they can get dirty and clog or wear out and get unreliable.

Since the manufacturer of the meter doesn't know what you are going to use the meter for it will always advise on the worst-case scenario regarding maintenance. And using it in a fish tank to measure a tad of fertilized tapwater is far from the worst-case scenario and it will wear out your meter much less...

That's about all I can say about it, can't tell you what to buy nowadays... The market is flushed and the outside of the device never shows the quality. I've used cheap meters that did it pretty good and used expensive ones that did a crapy job. After a while of playing with it, I became rather unsure if the importance of pH in a fish tank is worth investing money in to know it. IMHO it's not, but this is a personal decision you should make yourself... The opinions in this vary as much as the numbers of meters out there I guess...

, was going to link you in m8 for your input

pH pens are a minefield IMHO - I do like the BNC type as you can then choose any BNC probe to use on the unit.

 

[Hanuman]

View attachment 184931

cries in wallet

Are there some good options around the 50-75 euro range?
Even for the Hanna pens I was hoping to spend less.

I just want some stable CO2 my dudes 😅

The PH pen or probe will not provide you a stable CO2. You will.
First look at why your CO2 is not stable. Leaks? Poor circulation and water flow pattern? Proper gas exchange?

All this you can do without a PH Pen.

If you want to get a rough idea of your PH profile at a cheap cost then take a cheap PH pen. Then adjust accordingly.

 

[Zeus.]

The drift in a pH pen/probe in 8hrs will be minimal IMO. That's good enough
The next day when redoing profile ignore the pH reading and just log the drift.
I rarely calibrate my probes as I see it as pointless waste of time, just note the drop from degas tank water till lights on and drift from lights on till CO2 off. Then if stable from lights on till CO2 off (I use 0.1pH drift as stable) then what colour is the DC a few hours after lights on (only is stable (ish) pH

 

[zozo]

I do like the BNC type as you can then choose any BNC probe to use on the unit.

Over 20 years ago I bought a Hanna GroCheck permanent meter, its manual said the disposable BNC probe should be replaced once a year. I used it for a year then the meter got stored in the shed and actually forgot about it. After about 15 years later I found it back, plugged it in, calibrated it and the darn thing was still working as if it was new. After that, I still used it for a few years with its original first probe...

Finally, I did put a new after market BNC probe on it and since I had no proper use for it I gave it to a friend with a swimmingpool he's still using it today as far as I know.

 

[Hufsa]

For the pH resolution of 0.01 pH to be useful, doesnt accuracy also have to be 0.01?
If the accuracy is the same on both meters, what is the point of the higher resolution readout?

Does anyone have an answer to this question?

The PH pen or probe will not provide you a stable CO2.

Of course not, but it will let me know if I am getting close or not. That is what I want it for. It is a tool for me to be able to do the job of getting CO2 tuned in right. I dont think I have ever said that the ph pen is going to directly give me stable CO2. But it will help me know what is going on.

First look at why your CO2 is not stable. Leaks? Poor circulation and water flow pattern? Proper gas exchange?

I dont actually know if my CO2 is unstable. I have algae, which suggests it. But I dont know for sure. I have already checked for leaks. Circulation and water flow pattern is very good. Gas exchange is quite high and my injection rate is wild especially for a 20 ppm target.

All this you can do without a PH Pen.

I want slightly accurate ph measurements in order to know what's going on. This should not be unreasonable to want

If you want to get a rough idea of your PH profile at a cheap cost then take a cheap PH pen. Then adjust accordingly.

This is why I started the thread. I had questions about which mid range PH pen to go for.


Maybe I am being unfair here but I just wanted some help with my original questions, not to know the theoretical most maximally effective way to measure ph, its way out of my budget. Maybe I should have started with a disclaimer about that, if so I apologise, I will do better. Just getting a bit frustrated if im being honest

 

[Wookii]

Does anyone have an answer to this question?

For the pH resolution of 0.01 pH to be useful, doesnt accuracy also have to be 0.01?

Technically no. Meter 1 can have a resolution of 0.01pH, but an accuracy of 0.1pH, and meter 2 a resolution of 0.1pH and an accuracy of 0.1pH.

So for example, say your pH is 6.58pH, meter 1 should report between 6.48pH-6.68pH and meter 2 should report 6.5pH-6.7pH. 0.1pH should be plenty accurate enough for our purposes, but it will depend how deep your OCD runs

I have this Hanna probe:

HI-11102 HALO Glass Body Gel Filled pH Electrode with Bluetooth®

No need for a pH meter. Free to use Hanna Lap App for tablet or mobile phone. Flexible, accurate and easy to use.

www.hannainstruments.co.uk

Likely a bit too spendy for the budget you've allocated, but its highly accurate - the most amount of drift I have had over a 6 month period between calibrations is 0.2pH - and has data logging whilst connected to a blu-tooth device,

 

[Hanuman]

Maybe I am being unfair here but I just wanted some help with my original questions, not to know the theoretical most maximally effective way to measure ph, its way out of my budget. Maybe I should have started with a disclaimer about that, if so I apologise, I will do better. Just getting a bit frustrated if im being honest

Go for a cheap pen if budget is a the primary concern. See how it goes. It's not like you will use the pen everyday and as said above what you want to know is the drop, not the actual PH. 0.1 will suffice.

As for all the comments you got from me and others they are meant to provide some background/knowledge/experience and perhaps for you to see that not all is black and white, specially when it comes to PH testing. If someone had told me years ago that a probe was a better choice I would not have wasted my time with PH pens.