Figured it out! ppt in this conversion is part per thousand (PPT) - sorry I always worked in parts per trillion (ppt) so the units threw me way off.
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Sorry, yes, per thousand
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What about the calibration solution? Have you tested both meters with that?
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Let me see what it says with the solutions, I haven’t done that
Top reading is EC of 3.73 mS/cm
Middle reading is TDS of 2.66 ppt
Bottom reading is 1611 ppm of TDS
If we do the math, your ppm meter is likely in Hanna (500) scale.
And I think everything agrees!
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Try this: Manic Botanix | Hydroponic Calculators
The tds between the two meters is off. So the apera isn’t calibrated correctly or the other meter is jacked up. Thinking something happened during calibration
I don’t think so. I think they agree. (or are close) Apera is in Truncheon (700) scale and the other is in hanna (500)
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You’re right! Thought it read in the manual that is was set for .5
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Yep, default is .71
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Think I picked ya up on another thread…
Switch both to EC and it should be good, I’m on a Live chat with Apera. lets see if they answer
Hello, thank you for reaching out. The PC60 has an adjustable TDS scale that you can change to the scale you need and the factory default is the 700 scale.
Rest of his response:
The ppm 700 scale is based on measuring the KCl or potassium chloride content of a solution. The ppm 500 is based on measuring the NaCl or sodium chloride content of a solution.
IN the conversion chart, his first reading is the ref or 3.73 which is off my chart, but if you add the 3 and the .7 that would give you 2100+490 for the truncheon reading and 1500 + 300 for the hanna. which would be 2590 and 1800 so not perfect, but close.
Here I’ll take a reading of the cal solutions with both meters one sec. And I’m not saying one is right or one is wrong. I just want to know how to get a ppm reading I can understand from my apera
The apera is reading it directly - in your second picture. 2.66 ppt (or 2660 ppm) truncheon scale
It says it’s adjustable from .7 scale to .5 scale. Let me go through the manual and I’ll let you know when I find out how.
Looks like the same scale now. 1100 vs 1051
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