# good ph meter on a budget.



## plantnoobdude (19 Jun 2021)

right now i'm solely relying on my dropchecker for co2 concentration. i'd like a ph meter that comes with calibration fluid, rn my co2 dc is a good yellow color through out the photo period, but "over 30ppm" isn't very useful info.under 40 pounds is good


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## erwin123 (20 Jun 2021)

Amazon product

no one has answered yet so I'll just share that I bought the Apera ph20 from amazon. It has 3000 reviews on amazon USA. Out of the box, the calibration was just 0.1 off from the 4.0/7.0 calibration solution.  their premium model PC60 does TDS as well but I understand that you don't actually need an expensive TDS meter for aquarium purposes.


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## plantnoobdude (22 Jun 2021)

many thanks @erwin123


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## Nick potts (22 Jun 2021)

If you can stretch i little more on the budget then Hanna make some very good meters, very reliable and excellent quality









						HI-98100 Checker Plus pH Tester
					

The easy to use Checker plus is a real favourite with students and researchers due to its clear LCD display and long thin pH electrode. The checker offers automatic calibration and buffer recognition, calibrated buffer tags, and a stability indicator.




					www.hannainstruments.co.uk


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## plantnoobdude (22 Jun 2021)

thanks nick, will consider


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## X3NiTH (23 Jun 2021)

I have the Hannah pH probe mentioned above and it appears accurate, the device is easily calibrated for either freshwater or saltwater profile, normally the device when calibrating asks for pH7 calibration solution first and then pH4, for Saltwater systems if you use pH10 calibration solution instead of pH4 solution the pen will detect this and automatically change to calibrating for pH10. It’s not entirely necessary to do this but at least the option is there to further fine tune the pens accuracy depending on the pH profile of the aquarium in question.


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## plantnoobdude (20 May 2022)

Nick potts said:


> If you can stretch i little more on the budget then Hanna make some very good meters, very reliable and excellent quality
> 
> 
> 
> ...


due to budget constrains I was not able to buy this product at the time.
I would like to now reconsider. but I noticed the "accuracy" is listed as 0.2. what exactly does this entail? the PH could be off by 0.2 every time you measure?
how often should the meter be callibrated?
and im not exactly sure how storage with KCl works, anyone able to explain? cheers,


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## brhau (20 May 2022)

plantnoobdude said:


> I would like to now reconsider. but I noticed the "accuracy" is listed as 0.2. what exactly does this entail? the PH could be off by 0.2 every time you measure?


Hanna makes different quality pH meters. Accuracy 0.2 means the reading is accurate to within 0.2 pH units. The Hanna 98129, by contrast, has an accuracy within 0.05. It's more expensive, however. They also have one accurate to 0.1.



plantnoobdude said:


> how often should the meter be callibrated?


I don't need to calibrate it often. I measure the pH standard that's closest to my tank water. If it reads correctly, I don't calibrate. I maybe have to do a calibration once every 3 weeks or so. If you were working in a lab, you'd do a 2-point calibration every time.



plantnoobdude said:


> and im not exactly sure how storage with KCl works, anyone able to explain? cheers,


The cap holds the probe in a small pocket. You add a few drops of saturated KCl (storage solution) in that pocket when closing the cap to protect the probe.


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## plantnoobdude (20 May 2022)

brhau said:


> Hanna makes different quality pH meters. Accuracy 0.2 means the reading is accurate to within 0.2 pH units. The Hanna 98129, by contrast, has an accuracy within 0.05. It's more expensive, however. They also have one accurate to 0.1.
> 
> 
> I don't need to calibrate it often. I measure the pH standard that's closest to my tank water. If it reads correctly, I don't calibrate. I maybe have to do a calibration once every 3 weeks or so. If you were working in a lab, you'd do a 2-point calibration every time.
> ...


thank you for the response! Im still not sure what the accuracy means. does it means its within 0.2pH of the true value? then the range could vary by 0.4pH from each test no?

I will look at their other models, as they also seem reasonably priced.



brhau said:


> I don't need to calibrate it often. I measure the pH standard that's closest to my tank water. If it reads correctly, I don't calibrate. I maybe have to do a calibration once every 3 weeks or so. If you were working in a lab, you'd do a 2-point calibration every time.


sounds good!


brhau said:


> The cap holds the probe in a small pocket. You add a few drops of saturated KCl (storage solution) in that pocket when closing the cap to protect the probe.


also makes sense! thank you.


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## brhau (21 May 2022)

plantnoobdude said:


> thank you for the response! Im still not sure what the accuracy means. does it means its within 0.2pH of the true value? then the range could vary by 0.4pH from each test no?


Theoretically yes, but I think it's more likely the meter will systematically be off in the same direction, in which case the range would vary by less than 0.2. That said, I also think it's worth paying a little more to have a more accurate meter.


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## plantnoobdude (21 May 2022)

brhau said:


> Theoretically yes, but I think it's more likely the meter will systematically be off in the same direction, in which case the range would vary by less than 0.2. That said, I also think it's worth paying a little more to have a more accurate meter.


Hi, thank you. that makes sense. what pH meter do you use?


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## brhau (21 May 2022)

plantnoobdude said:


> Hi, thank you. that makes sense. what pH meter do you use?


Hanna 98129


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## bazz (21 May 2022)

If you are thinking of using one in soft water I would save your money and your time. I replaced a brand new HM Digital PH-80 Water Resistant pH Meter with a HI-98100 Checker Plus pH Tester and had exactly the same problem, later finding out PH meters are pretty much useless in soft water. For reference my water is <5dGH and <1dKH.
Cheers!


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## brhau (21 May 2022)

I have blackwater tanks and keep the conductivity below 50 us/cm, KH 0, GH 0. To measure the pH, I take a 20 ml sample from each tank and dissolve 1 or 2 flakes of kosher salt in the sample. That increases the conductivity to greater than 200 us/cm, at which point the pH readout works fine.


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## plantnoobdude (21 May 2022)

brhau said:


> I have blackwater tanks and keep the conductivity below 50 us/cm, KH 0, GH 0. To measure the pH, I take a 20 ml sample from each tank and dissolve 1 or 2 flakes of kosher salt in the sample. That increases the conductivity to greater than 200 us/cm, at which point the pH readout works fine.


thanks for the tip! my water is quite soft aswell, 45~50 TDS and 0kh with 2gh.


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## dw1305 (25 May 2022)

H all,


bazz said:


> If you are thinking of using one in soft water I would save your money and your time. I replaced a brand new HM Digital PH-80 Water Resistant pH Meter with a HI-98100 Checker Plus pH Tester and had exactly the same problem, later finding out PH meters are pretty much useless in soft water.


That is the real issue, as you approach pure H2O pH becomes less and less meaningful as a parameter and very small additions of acids <"and bases"> cause <"huge variations in pH">.  I use <"shell attrition"> in my Ramshorn snails as a rough proxy for dKH (and therefore indirectly pH) now. 


brhau said:


> To measure the pH, I take a 20 ml sample from each tank and dissolve 1 or 2 flakes of kosher salt in the sample. That increases the conductivity to greater than 200 us/cm, at which point the pH readout works fine.


I agree with @brhau  you can get around the problems in measurement to some degree by adding a <"neutral salt (usually NaCl)"> to the water sample you are testing. It doesn't change the pH (the Na+ and Cl- are charge balanced)  but it does mean there are more ions in solution and the meter stabilises more quickly.

You still only have a pH "snap-shot", which is the advantage of the snail shells, they are a real time data logger.

cheers Darrel


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## jaypeecee (25 May 2022)

dw1305 said:


> You still only have a pH "snap-shot", which is the advantage of the snail shells, they are a real time data logger.



Hi Darrel (@dw1305)



JPC


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## brhau (25 May 2022)

dw1305 said:


> That is the real issue, as you approach pure H2O pH becomes less and less meaningful as a parameter and very small additions of acids <"and bases"> cause <"huge variations in pH">. I use <"shell attrition"> in my Ramshorn snails as a rough proxy for dKH (and therefore indirectly pH) now.
> I agree with @brhau you can get around the problems in measurement to some degree by adding a <"neutral salt (usually NaCl)"> to the water sample you are testing. It doesn't change the pH (the Na+ and Cl- are charge balanced) but it does mean there are more ions in solution and the meter stabilises more quickly.
> 
> You still only have a pH "snap-shot", which is the advantage of the snail shells, they are a real time data logger.


True, and possibly context-dependent?

The phytoplanton play a large role the pH fluctuation of large bodies of natural water. And, "_It goes without saying that this pH swing cannot be observed in an aquarium only because we cannot reproduce the amount of light which falls in the Lake."  _In a closed-system blackwater tank, there is low light and low plant mass.
Whatever the botanicals are releasing in the aquarium appears to buffer the water. This idea is based on my observation that pH is proportionally more difficult to lower (and keep low) using acid the more darkly stained the water is.
I don't have a large enough sample size to say how much the pH in my tanks fluctuates overnight. But despite only taking "snapshots," so far I see very low fluctuation in pH across my tanks. Typically, I only see it drift upward. I'll take more early morning time points to see if I can measure it.

The snail idea is a good one, but it's a time-averaged logger, rather than a real-time logger. Because my tanks are both 0 KH and intentionally acidic, I don't think any snails can survive in them.

Cheers


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## dw1305 (25 May 2022)

Hi all, 


brhau said:


> Whatever the botanicals are releasing in the aquarium appears to buffer the water.


I think they will <"buffer the water"> to some degree. 


brhau said:


> The phytoplanton play a large role the pH fluctuation of large bodies of natural water. And, "_It goes without saying that this pH swing cannot be observed in an aquarium only because we cannot reproduce the amount of light which falls in the Lake." _In a closed-system blackwater tank, there is low light and low plant mass.


If you don't have many plants it will limit the pH variation upwards, just because you will never have that much "excess" oxygen. 


brhau said:


> The snail idea is a good one, but it's a time-averaged logger, rather than a real-time logger. Because my tanks are both 0 KH and intentionally acidic, I don't think any snails can survive in them.


Point taken, I have had some tanks <"where snails won't survive">, and <"black-water is a special case">.   For me even our rainwater it is still a lot harder and more ion rich than the rio Negro and I don't keep any real black-water fish, because I know they can't reproduce successfully, even if long term maintenance isn't an issue.   

cheers Darrel


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## brhau (25 May 2022)

dw1305 said:


> If you don't have many plants it will limit the pH variation upwards, just because you will never have that much "excess" oxygen.


There are a lot of plants, but I don't know whether they respire much dissolved CO2. The floating plants, I imagine, respire to the atmosphere? The submerged plants are a lot of slow growers (java fern, mosses). And the fast growers (_Ceratopteris thalictroides_, _Mayaca fluviatilis_) don't require much CO2 capture to begin with. I would imagine the pH would be much more variable in a higher energy tank.

-B


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