pH sensors that don't have to be calibrated

[jonpcar]

Nice job Kato! Congrats! I’ll be looking forward to the updates. pH has definitely moved up my list since I “lost” the ability to monitor the acid level in my Stenner pump muriatic acid tank (due to the eTape measurement device failure in muriatic acid). The best way to get feedback on whether or not an acid injection was “successful” is to measure the effect it had, or didn’t have, on water chemistry...your pH monitor.

I’m also particularly interested in a “one point calibration” method and whether that turns out to be useful. That could allow chemical “drop testing” and calibration of the pH probe on a schedule that could be as low as once every few months or so. It seems that on your device, the one point calibration method is for a specific pH value (7.0 from memory...don’t hold me too that). But, can the software simply compensate for any changes read from a probe that is drifting in its calibration? An offset type adjustment? And would that method be accurate enough for most cases?

 

[cmc0619]

Looks the same as what I ordered: 4-20mA converter on Amazon
Double the price at $8 for two, but you do get two day delivery.

They were on Amazon all this time?!

 

[MyAZPool]

TADA!!!!

Its finally done. What an ordeal. After pushing the wrong button on the controller and inadvertently re calibrating the probe to the wrong levels. I did a 3 point calibration this morning.

Last night I finished the wiring into my controller that took a 4-20ma converter and wired it into an ADC in the MegaIO card on my Rpi. A bunch of back and forth to calibrate the converter (who’s instructions were wrong) and its installed. Did a quick flow in NodeRed and now I have a pH gauge on my phone/iPad/computer.

Going to write some flows later this today or this weekend to email me when my pH hits 8 so I get a nice warning. Although I cant see that happening as I am obsessed at looking at my pH levels constantly.

Need to figure out some better Alexa integration so that I can ask Alexa to tell me my pH and temperature.

Might now consider auto dosing acid based on the pH reading. Also thinking about integrating a pressure sensor since that should be fairly easy now.

@Katodude,
Okay A. That's it... I want one too!! SUPER nice... Great Job. Yea that @cmc0619 dude is all over the place helping us all out. I sure owe him (and you) many thanks for all of the RPi/dashPanel effort.

Where do I start? Do I need another RPi? As @cmc0619, can attest, I may have already found a reason for #2 anyway. If you have time, maybe you can summarize the requirements, equipment, code, steps etc., so us noobs can have a toy like this for ourselves?. ..

I'm already wondering if rstrouse can integrate something like this into the node.js-poolController=dashPanel?
Again, very nice... Hope D. is doing okay.
r.

 

[susa]

So I am shopping around for a pH sensor that I want to mount inline in my plumbing and hook up to my automation system.

Simpool Ph works for our pools, link in sig

 

[Katodude]

They were on Amazon all this time?!

I know right?!?! So of course I ordered another.

 

[Katodude]

I’m also particularly interested in a “one point calibration” method and whether that turns out to be useful. That could allow chemical “drop testing” and calibration of the pH probe on a schedule that could be as low as once every few months or so. It seems that on your device, the one point calibration method is for a specific pH value (7.0 from memory...don’t hold me too that). But, can the software simply compensate for any changes read from a probe that is drifting in its calibration? An offset type adjustment? And would that method be accurate enough for most cases?

Since the probe was already out I opted for full 3 point calibration. But single point calibration would probably be sufficient for pool use since all we care about is a value in the 7's and 8's. The kit that I bought had all three solutions so why not do it all out. I resealed the bottles put them in a food saver bag and vacuum sealed them for the next time. The sensor say it can go a year without calibration, but I will probably do it every 6 months or so.

You can read up on the calibration theory in the Ixian manual.

https://www.atlas-scientific.com/files/pH_transmitter.pdf

 

[Katodude]

Okay A. That's it... I want one too!! SUPER nice... Great Job. Yea that @cmc0619 dude is all over the place helping us all out. I sure owe him (and you) many thanks for all of the RPi/dashPanel effort.

Where do I start? Do I need another RPi? As @cmc0619, can attest, I may have already found a reason for #2 anyway. If you have time, maybe you can summarize the requirements, equipment, code, steps etc., so us noobs can have a toy like this for ourselves?. ..

I'm already wondering if rstrouse can integrate something like this into the node.js-poolController=dashPanel?
Again, very nice... Hope D. is doing okay.
r.

I will post a full bill of materials and steps at a later date. But a good start is what @cmc0619 posted in the wifi filter pressure post. Fundamentally you need a pi, and ADC, and a 4-20ma converter. A 5v power supply for the pi, and a 12v powersupply for the probe and converter.

This is the kit I bought from Atlas. Its a little pricey but industrial grade.

Industrial pH Kit | Atlas Scientific

Are you working with a PLC and aren’t sure what parts are right for you? This is the Atlas Scientific industrial pH kit. It comes with everything you need to take high accuracy, interference-free readings with a PLC.

atlas-scientific.com

 

[Katodude]

Just in case anyone cares, my pH is 7.6 and steady.

Added the flows to email me when the pH goes over 7.9. It was incredibly easy to do. So now as long as the pH is over 7.9 it will email me every 12 hours to remind me.

Might have to have some fun and customize the warning messages calling me all sorts of nasty names when it happens.

 

[CRAD_oz]

Nice work with getting it up and running.
I found myself Checking my pH log every morning while waiting for my coffee instead of work emails.
I also had/have the emails when the pH reaches a target but I had to increase the Deadband to stop an email been sent every time the pH value toggled to the set value and the 0.1 above or below which does happen when the pump is running. Not sure if you system will have this issue?
Below is a trend from my system showing where I added a bit of Alk and started to aerate to get the pH up a bit(I was bored looking at 7.3)

 

[Katodude]

So now that this has been running for a while a couple of observations.

My pH is far more stable than I ever thought. It really has not moved much. It slowly creeps up, but much slower than I used to think with the drop test.

Which leads to observation #2. My eyes are terrible. On the drop test, I read 7.8 as well over 8. I have been over dosing my pool with acid for a while now.

 

[MyAZPool]

So now that this has been running for a while a couple of observations.

My pH is far more stable than I ever thought. It really has not moved much. It slowly creeps up, but much slower than I used to think with the drop test.

Which leads to observation #2. My eyes are terrible. On the drop test, I read 7.8 as well over 8. I have been over dosing my pool with acid for a while now.

 

[sts]

Hmmm, this seems interesting. I wonder if I can build a correlation between FC, Orp, CYA, temp and pH. Be nice to have some type of formula to make the ORP reading more useful.

Curious, have you been using the Atlas Scientific Pool Kit? How is it working for you?

 

[Katodude]

I have been using the industrial pH sensor for about 2 years now. It has been working great. I just the check the calibration yesterday and it dead on. I am really happy with that addition.

Now that I also upgraded my NodejsPoolController it shows my pH in my dashboard which is nice.

I keep my pH at around 7.8 or 7.9 where it is very stable. I have managed to reduce my CH to about 230 so my CSI is reasonable at that level. I have not added acid in a long time.

 

[sts]

I have been using the industrial pH sensor for about 2 years now. It has been working great. I just the check the calibration yesterday and it dead on. I am really happy with that addition.

Now that I also upgraded my NodejsPoolController it shows my pH in my dashboard which is nice.

I keep my pH at around 7.8 or 7.9 where it is very stable. I have managed to reduce my CH to about 230 so my CSI is reasonable at that level. I have not added acid in a long time.

Thanks! Thinking about purchasing it. Do you know if there is any way to add a pressure sensor to the Atlas Scientific Pool kit. I see pH, ORP, temp, and the offer flow (meters are expensive) and others, but not seeing pressure. Thought it would be a quick way to see if filter needs to be cleaned. I can still run out and look, but would be nice to have it all in one place.

 

[Katodude]

I just bought a 0-5v pressure transducer. I will install it directly on the filter. I did the wiring on my controller but have not installed it on the filter yet.

 

[Turbo1Ton]

Thanks! Thinking about purchasing it. Do you know if there is any way to add a pressure sensor to the Atlas Scientific Pool kit. I see pH, ORP, temp, and the offer flow (meters are expensive) and others, but not seeing pressure. Thought it would be a quick way to see if filter needs to be cleaned. I can still run out and look, but would be nice to have it all in one place.

You may check out this thread here... Alternative Pool Automation and Sensor/Chemical Control and Integration

I know myAZPool used a pressure sensor and wired it up.

--Jeff

 

[sts]

You may check out this thread here... Alternative Pool Automation and Sensor/Chemical Control and Integration

I know myAZPool used a pressure sensor and wired it up.

--Jeff

Thank you for pointing out the thread!

 

[sts]

I just bought a 0-5v pressure transducer. I will install it directly on the filter. I did the wiring on my controller but have not installed it on the filter yet.

Thanks for the update. I think I may be a little confused. Thought you were using the atlas pool kit with the industrial ph probes. From further reading, I believe you are using a raspberry pi solution with the atlas industrial ph probe. Can you confirm, are you using the arduino based pool kit or are you a raspberry pi solution? In any event, hope things go well with the pressure transducer.

 

[Katodude]

I am running a RaspberryPi with NodeJSPoolController on it. I have a relay board and Mega Industrial board from SequentMicrosystems. The Mega-Ind has 4-20ma, 0-10v inputs and a RS-485 port on it. I feed the 4-20ma input from an Atlas Scientific IXIAN board that is connected to the Industrial pH probe. I chose the IXIAN board because it has a display and I can calibrate the probe right from the board. You can get away with some cheaper stuff from Atlas Scientific since NodeJSPool can do the calibration. I would still recommend the Industrial Probe for both not having to calibrate often and longevity.

 

[setsailsoon]

Thanks to all on this thread. I'm finally getting my OB pool project underway and I plan to build my own automation in parallel with the project execution. This thread is a huge education for me. My wife is very skeptical. She can't stand my "playing around" with Rpi's and ESP 32's. Not sure why. But she was that way when I took over our first pool from the pool service with TFP when I got a lot of remedial training from @kimkats and many of the other experts still here. That worked out pretty well for both of us. Hopefully I'll understand this enough in time to put it in the field.

Chris