Automated testing

Request new hardware or ideas for the controller
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lnevo
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Automated testing

Post by lnevo »

With all these automated Alk testers and now Neptune coming out with their Alk, Cal, and Mag testing automation....what can we do from an open source / RA perspective.

I'm sure we can improve on whats out there and make something great. I don't have the chemistry background to do it, but I'm sure we can code whats needed.

Anyone have any ideas we can share and build on?
89delta
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Re: Automated testing

Post by 89delta »

Where there is a will there is a way......Have always followed you coding examples to use myself and playing with the Particle Photon that was a major thread on testing for Nitrates,Nitrites and Ammonia.
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lnevo
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Re: Automated testing

Post by lnevo »

89delta wrote:Where there is a will there is a way......Have always followed you coding examples to use myself and playing with the Particle Photon that was a major thread on testing for Nitrates,Nitrites and Ammonia.
You have any links?
89delta
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Re: Automated testing

Post by 89delta »

lnevo wrote:
89delta wrote:Where there is a will there is a way......Have always followed you coding examples to use myself and playing with the Particle Photon that was a major thread on testing for Nitrates,Nitrites and Ammonia.
You have any links?
https://community.particle.io/t/sensors ... ite/6379/8

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lnevo
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Re: Automated testing

Post by lnevo »

Interesting...what do we need to measure co2???

https://reefbuilders.com/2017/10/18/sen ... -just-200/
tngo
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Re: Automated testing

Post by tngo »

I've searched around and the way to sense dissolved CO2 in water is to get a NDIR that senses CO2 gas and wrap it with a CO2 permeable membrane but impermeable to water such as expanded polytetrafluoroethylene(PTFE) tube or sleeve. It's explained in the paper that I linked. From the CO2 number and pH we can calculate the alkalinity in code.

Possible sensor
http://sandboxelectronics.com/?product= ... peberry-pi

CO2 Membrane
http://ipeweb.com/index.php/products/eptfe-tubes

Research paper describing the method and the diffusibility of the membrame.
http://ecohydro.ires.ubc.ca/pdfs/Johnso ... ,68-78.pdf

Tim
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lnevo
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Re: Automated testing

Post by lnevo »

Very cool Tim!!! This could be a real breakthru. Roberto, whats your thoughts?
rimai
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Re: Automated testing

Post by rimai »

Maybe something like this?
http://www.pro-oceanus.com/mini-co2.php
Roberto.
tngo
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Re: Automated testing

Post by tngo »

That probe would be a neater package. Though I'm not sure what the copper/antifouling is for. Also, not sure what the cost for this would be.

Tim
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lnevo
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Re: Automated testing

Post by lnevo »

That is an analog sensor so need additional circuitry for analog 2 digital. The digital signal is a RS232 so more work involved I think, whereas the other is I2C.
rimai
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Re: Automated testing

Post by rimai »

All our expansion modules are analog and I use an analog to I2C chip, so not much different.
Roberto.
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lnevo
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Re: Automated testing

Post by lnevo »

Cool so just a matter of cost on that probe and some math?
tngo
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Re: Automated testing

Post by tngo »

Yeah, the Seneye will reportedly try and do it for $200. Also the accuracy of alkalinity value will be affected by the pH and CO2 probes accuracy.
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lnevo
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Re: Automated testing

Post by lnevo »

Yeah, for the price of the Seneye, it's not a terrible purchase. Just won't be able to automate anything off it or integrate it into the RA data. Maybe I'll figure out how to scrape it off the web interface and push it to a custom variable :)

If we could do the same it would be cool though :)
tngo
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Re: Automated testing

Post by tngo »

I checked on the probe that Roberto linked and thats about $7K. The probe from the research paper is about $720. The one I had linked is rated from 400ppm to 10000ppm which is out of our detection requirements. Average dissolved CO2 in seawater is around 350ppm. However when looking up the CO2 probe I get varying specs even though they look pretty much the same. In the following link the sensor is rated from 0-2000ppm but with an accuracy of 200ppm. The accuracy maybe reduced through longer average sampling. Not sure if it will be viable but I'll try and look some more. Absolute value of alkalinity will probably deviate a large amount, but possibly large sampling and weighing the final number by a titrated calibration value might work.

https://www.seeedstudio.com/Grove-CO2-S ... -1863.html

Tim
tngo
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Re: Automated testing

Post by tngo »

The following probe has better accuracy numbers.

https://www.tindie.com/products/Blueber ... sor-ee893/
tngo
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Re: Automated testing

Post by tngo »

Here's a website that goes through the calculations for pH, total alkalinity, CO2 and pCO2. It does it backwards from what we would want namely obtaining CO2 from total alkalinity, whereas we would want total alkalinity from CO2 and pH. They also do an iterative process to lock down a converging pH value and alkalinity which is interesting possibly allowing us to get a more stable value if implemented. There is source code on one of the tabs showing the constants that he used and how he does the calculations in code.

http://biocycle.atmos.colostate.edu/shiny/carbonate/

Tim
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lnevo
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Re: Automated testing

Post by lnevo »

tngo wrote:The following probe has better accuracy numbers.

https://www.tindie.com/products/Blueber ... sor-ee893/
I like that this one is optical.
rrodriguess
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Re: Automated testing

Post by rrodriguess »

I have a planted aquarium with CO2 injection. Would love to have one of this.

Rafa
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rrodriguess
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Re: Automated testing

Post by rrodriguess »

Any progress on that? Maybe we could open some kind of crowdfunding to help somehow?
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lnevo
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Re: Automated testing

Post by lnevo »

Nothing new, but seneye supposedly released an API on github to access the data. Opens up some good possibities :)
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