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PH monitor suggestions - continual use

jaypeecee said:
I agree with the reservations of others about continuous pH monitors. That's why I would be very hesitant about using one of these to control CO2 injection
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I've made no mention that this has ever been my intention; merely to have a rough idea how the CO2 levels change over a 24 hour period and longer.
jaypeecee said:
Something's amiss. The Hanna buffers permit calibration to two decimal places so how can they then claim that it's accurate to three decimal places, i.e. +/-0.005pH?
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I appreciate there's always margin for error and results also rely on 'ideal' conditions; Hanna do make a 'Millesimal Buffer Solution' which is accurate to ±0.002
so could possibly support the ±0.005 of the HI-11102 HALO device although I'm just guessing here.

I think if I need a device this would be more than accurate for my needs and is only to keep an eye on the CO2 levels and monitor them out of interest as much as anything else.
Thanks for your input though
 
Hi all,
jaypeecee said:
Something's amiss. The Hanna buffers permit calibration to two decimal places so how can they then claim that it's accurate to three decimal places, i.e. +/-0.005pH? Not that there's anything wrong with calibrating to two decimal places.
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Andrew Butler said:
There is of course margin for error but this is just to try and answer your question here.
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I've been thinking about this, and I may be wrong, but isn't there a more fundamental issue, which is that the decimal places on pH values can differ by several orders of magnitude, because pH is a -log^10 scale representation of the hydrogen ion activity?

I think that implies that the 3rd decimal place at pH4, is the same as the unit at pH7? You've gone through three orders of magnitude, from 10^-4 to 10^-7.

When-ever I think that I understand pH something else comes up that makes me think I don't at all.

This is a "weak acid / weak base" <"titration curve">. I think that is where we are when we add CO2, to 4dKH solution, and the bit we are interested in is somewhere around the equivalence point.

wawb.gif
cheers Darrel
 
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Must admit I'm enjoying reading the debate...however are we really concerned about measureong ph to the 1/1000th when we does EI based on teaspoon measurements!

Sledgehammer and walnut springs to mind
 
Andrew Butler said:
I've made no mention that this has ever been my intention; merely to have a rough idea how the CO2 levels change over a 24 hour period and longer.
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Hi @Andrew Butler

Apologies. I am fully aware that you had no plans to use the pH monitor to actually control CO2 injection. I obviously implied otherwise. Have you had a chance to look at some of my suggestions?

JPC
 
jaypeecee said:
have no need for actually measuring pH to an accuracy of +/-0.001
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Completely agree with you here, I guess just the more accurate a device is the less margin for error.
jaypeecee said:
Have you had a chance to look at some of my suggestions?
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I've had a very quick look but need to sit down next year and have a proper look through them, thanks though.
I do see the Hanna bluetooth version as something that could work for me; I just need to look into things a bit more as money soon starts getting out of hand and I could just use my handheld.
Very interested to look into options as I'm in no rush.
 
Wookii said:
I wanted to monitor Ph wirelessly, and more importantly have the results easily graphed in an app, so I've just treated myself to one of these (an early Christmas present from me to me lol):

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

It's blue-tooth, wireless (500 hour battery) so you need to be in range to log the data (there is a dedicated Hanna app), but I'll just leave an old iPhone plugged in near it, with the app running, to record the data.

It still needs recalibrating regularly to maintain accuracy (Hanna advise weekly), but I'll see what the drift is like over time. It looks to be a pretty accurate unit out of the box at ±0.005 pH, so as long as it stays accurate within the ±0.05 pH it'll be sufficient for me - and I'll see how long it maintains that lower spec accuracy and recalibrate based on that interval instead.

There are a few variants, including one in a titanium tube for beer if you wanted something more durable - but they all use the same sensor bulb I believe. I don't know what their lifespan is like, but their applications suggest they are robust enough for ongoing monitoring. Certainly when speaking to their tech support, they suggested longer term monitoring would be fine, but just reiterated that the sensor would need regular cleaning and recalibration to maintain accuracy.

Personally I plan to just get a profile over 48 hours, and then recheck that profile every month or two to ensure it is consistent, as reinforcement for dropper checker monitoring (keeping it in storage solution in between). As Darrel says, I personally wouldn't rely on it for CO2 levels, but it will be nice to see the actual Ph effect - and I'm a massive geek for gadgets like this!
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What's your review 3 and half years later?
 
Hanuman said:
What's your review 3 and half years later?
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Hmmm, well, there's a story there - I managed to break mine about 6 months ago . . . . so being made of glass is a definite downside! Other Pro's and Con's:

It was incredibly stable, pH never drifted by more than about +/-0.2-0.3pH between calibration periods after prolonged storage.

The app allows you to log readings, and view them on a graph which is convenient, but it will only connect via blue tooth, so it means you need a spare device next to the tank to log the data. I get they can't include wifi because it consumes too much power for a watch battery powered device, but I'd have preferred they included a solid state chip on it to record the data internally so that you can download it later

There was also no easy way to hang the meter on the edge of the tank with the end in the water without a DIY hack of some sort.

All in all a good bit of kit, but a bit pricey, and a bit fragile for our purposes - there are probably better options out there, particularly with the probe on a cable so that it can be submerged to a better measurement point than the surface, but I'd imagine many wouldn't be as stable/accurate between calibrations.
 
Wookii said:
there are probably better options out there, particularly with the probe on a cable so that it can be submerged to a better measurement point than the surface, but I'd imagine many wouldn't be as stable/accurate between calibrations.
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This is the one I found last year but the lack of funds prevented me from buying it:

Egrowr - Connected hydroponic measuring device

Your plants' pH, conductivity and climate on your smartphone. Receive push notifications, analyze graphs and follow the measurements anytime, anywhere.
egrowr.com egrowr.com
 
I'm using a Milwaukee MC-122 with a smart plug. Originally I had it dangling into the tank via its cord but now I have it going into the outflow of my FX4 between the filter and the Cerges reactor, plugged into a 1" barb x 1/2" NPT x 1" barb Tee, sealed with a cable gland. Put it over a bucket once a month, turn off the filter, close valves, open cable gland, remove probe and recalibrate with 4.01 and 7.01 solution.
 
foxfish said:
I miss Andrew, he was an entertaining and active member, hope he is OK?
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I have had contact with Andrew recently and he is a little under the weather and had to give up on the hobby for the time being, I have sent everyone's regards and hopefully he will make a recovery soon enough and get back to some normality. Will keep him in my prayers.
 
MichaelJ said:
I have reached out to @jaypeecee (PM) a couple of times in the spring. Didn't hear back from him - which is unusual even when he is not posting. I hope he is doing good and just taking a break from the forum 🙏

Cheers,
Michael
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Just to let you know that I also had word from John, he is also under the weather and dealing with some issues, hopefully he will be around soon enough. Wishing him a speedy recovery also.
 
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