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DIY automated pH doser

whadeezlrg

Just Say Grow
Veteran
I guess it's value is relative to what you value your time as, even if it was $1000 it would pay for itself relatively quickly in my case. not to say achieving the same result for less money is anything other than a great idea.
 
150 usd for controller and pump is a bit too much. It can be done with about 30 usd if you use arduino board as controller and a cheap perisaltic pump off ebay. The PH probe is probably the most expensive bit of the system.

I totally agree with the ebay route. In my experience people have a hard time writing code with arduino and interfacing devices. The controller I referenced has a built in web server. No doubt arduinos can be powerful in the right hands though.
 

queequeg152

Active member
Veteran
go on ebay, search for PH analyzer.

boom.

i have several haach gli 53 and 63's. they are ideal for this task.

shitty ph probes are IMO not.

for constant online monitoring tasks you want a good quality probe with replaceable components.

try searching for "accuglass" they can be had for like 100 bucks.
 

Bennyweed1

Active member
Veteran
Yes I still use system. I dont normally rely on it during regular growth, but I have no problem leaving for extended periods of time.

As others said, their are way better methods I am sure, as there are to any problem. This was my solution 2 years ago because 2 years ago no one was talking about it. Atleast online it seemed.
 

glhydorponicsco

New member
I would like some more information on these GLI International p63's. I have one but no probe. Could some one please chime in and let me know about this AccuGlass probes and what model could work with my p63. The unit is set up for thier 5 wire differential probe so I do not know what other probes will work.
 

queequeg152

Active member
Veteran
they can be configured for every single electrode as far as i understand.

you might have to combine the shield wicks or ground wires etc onto one terminal... but from what i remember, the gli 53/63 has terminals for the reference ground, cable shield, and the thermocouple shield too.

trust me... these analyzers would be worthless if they were only good with those expensive ass GLI elctrodes...

what problem exactly are you having? you literallly just need to match up the reference, RTD, ph, electrolyte etc etc...

did you buy a digital PH electrode or something? those require serial communication... they will NOT work with a GLI 53/63.
 

glhydorponicsco

New member
I bought a p63 and spoke with Hach tech support and the Model # p63a1n1a1a1nnn which he stated the fourth place (a) is a denotation for the Differential Probes. The manual shows the connections for a Combination probe BNC type. I have not powered this unit up yet but the manual also shows that you can switch which probe you are using either a Differential or Combination. As of right now I only have a access to a Combination probe with a BNC connector. I was going to cut the connector off and wire it in but I want to know if this will work first. I do have a Differential probe on the way but did not want to spend $$ as I have access to a lot of BNC combination probes.

Also what do you use for your reference solution in the differential probe? Standard 7.0 reference solution like GH 7.01 or their $$ reference buffer
 

queequeg152

Active member
Veteran
I bought a p63 and spoke with Hach tech support and the Model # p63a1n1a1a1nnn which he stated the fourth place (a) is a denotation for the Differential Probes. The manual shows the connections for a Combination probe BNC type. I have not powered this unit up yet but the manual also shows that you can switch which probe you are using either a Differential or Combination. As of right now I only have a access to a Combination probe with a BNC connector. I was going to cut the connector off and wire it in but I want to know if this will work first. I do have a Differential probe on the way but did not want to spend $$ as I have access to a lot of BNC combination probes.

Also what do you use for your reference solution in the differential probe? Standard 7.0 reference solution like GH 7.01 or their $$ reference buffer

BNC type cheapo probes are IMHO not suitable for constant online measurements as most electrolyte gels and liquids flow out too quickly...

this means you get an excellent response time, but the probe might only last like a month before the dilution falls below calibrate levels. i say "most", because some gells are indeed very slow... i had a ph electrode made for me here for throw away measurements, i had them use a special gell in a traditional non servicable probe body because i dont really care if it takes 30 seconds to give me a stable reading... i just want it to last a full year or two in storage with very very infrequent usage.

anyway, by all means try it out with your collection of probes. i would just advise that you monitor the voltage of the probe at calibration and the slope as well.

regarding differential PH electrodes... yea most analyzers are going to accept a differential electrode. its not hard to do and makes the analyzers more flexable.

with the GLI 53 and 63, when you setup the sensor you will select regular combination eletrode and not differential.

you also need to make sure to reconfigure the thermistor/thermocouple setting and calibration constant( if it has one).

even if an analyzer were able to ONLY take differential probes... you can essentially trick them into running regular combination probes. the opposite is NOT true with combination only analyzers...

if i remember right, you simply jumper the electrode ground over to the solution ground... the end result being 0 volts?

you might have to split the ground cable in some fancy way so as to exclude noise or other interferance? i dont recall exactly, TBH,

but a conventional electrode will not have the same signal quality and will float around alot more, so an analyzer designed to ONLY run on a differential electrode might act erratically. also any self diagnostics in the analyzer will give you erroneous warnings?

anyway all of the above is moot because again, generally speaking:

a ph analyzer that accepts differential electrodes will also accept conventional analyzers without any issues.

a ph analyzer that accepts ONLY combination electrodes however will NOT accept all types of differential electrod (far as i know?) because you need the extra grounds for proper reference calculations? i think that would depend on whether or not the differential sensor amplifier circuit itself is combining the reference and standard, or if its just amplifying all of the potentials and allowing the analyzer to calculate the voltage?

anyway just read the manual. The 53/63 has a fantastic manual unlike the yokogawas.
 

glhydorponicsco

New member
Thank you for the reply. I appreciate all of the details. So what I'm measuring and the constant flow across the probe makes a conventional combination electrode almost useless if I am planing on constant monitoring.

As far a general maintenance of the and life of the differential PH electrodes. What do you have to do. Just change the reference solution and salt bridge every year?
 

queequeg152

Active member
Veteran
you dont replace anything untill it fails with the GLI differential probes anyway...

the components cost way to much to do it on a precautionary basis. my GLI probe still calibrates well thankfully... i think think it was ever used.

a regular electrode that is designed for laboratory SPOT ph measurement will simply flow electrolyte to quickly. meaning its going to dilute to nothing rather quickly.

days? weeks? months? probably weeks or months im guessing, but i would calibrate frequently.

again though the electrolyte formulation makes a difference, with most gels being much slower to flow, and hence slower to respond.

you can also get refillable electrodes though... provided your junction is not plugged or something, refilling will greatly extend your probes life. im guessing yours are not refillable though, they tend to be glass bodied, and much more expensive.

i think storing without electrolyte is also technically better... meaning if you needed to store it for a long period in dry conditions, draining the electrolyte would be better.
 
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