Soil EC probes have gotten cheap now, what to connect them to?

Biologist

Active member

• Oct 14, 2020

• #1

https://www.amazon.com/Conductivity-Waterproof-Salinity-Transmitter-Greenhouse/dp/B08H8N7VN8/

I've been reading a lot and seeing big growers use the Grodans GroSens etc. and that has trickled down where knockoff probes are affordable. What would I connect that to? What does it output? Ohms? Could I convert it to EC with a simple ohms to milliSeimens per centimeter chart?

 

Biologist

Active member

• Oct 14, 2020

• #2

Or maybe I should save myself the headache and use something like this which has temperature compensation?- https://www.amazon.com/gp/product/B08GQ7J7H9/

Which seems to be a 1/10th the price knockoff of https://www.tigersupplies.com/Products/FieldScout-EC-Meter-Probe-for-Soil-and-Water__TURECM-1-N.aspx which is $573 and mixed with the probe from the Hanna https://www.hannainst.com/hi98331-soil-testtm-direct-soil-ec-tester.html


I'd like to leave the probe buried in a pot the whole grow to monitor soil EC as I do drip irrigation and drybacks, I wonder if it would corrode?

 

Ringodoggie

Well-known member

Premium user

• Oct 14, 2020

• #3

Have you checked compatibility with Raspberry Pi?


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Biologist

Active member

• Oct 15, 2020

• #4

I haven't checked. I'm not very experienced with using a raspberry pi. I contacted Hanna about their probe and they said no it isn't meant to be kept buried long term. Until I can figure out the first probe I posted, I ordered the $61 Crisis one from Amazon. I can at least do some tests with it and see where my EC is and how that compares to the runoff I measure.

I do want to try to use the $16 probe eventually and maybe several at a time because I know my runoff readings can vary quite a lot between strains.

 

f-e

Well-known member

Mentor

Veteran

• Oct 19, 2020

• #5

I would crack open a $10 ec meter and wire that to your probes.

 

Biologist

Active member

• Oct 29, 2020

• #6

No one should buy that Crisis one from Amazon. I got the thing and it is wildly inaccurate. One freshly watered pot will be 10 ppm and the next 1000. It reads an aqueous solution correctly but soil is wildly off. Whether this is the case with other soil probes or just this one I don't know. But I'm returning this one. I have heard other rumors about expensive soil probes being like this and having wildly different results based on where you stick the probe in the same pot. Maybe I'll just stick with measuring the runoff.