meter calibration with EC instead of ppm solution?

my understanding was that PPM is derived from EC using a multiplier which differs from vendor to vendor and is inaccurate to begin with.

if that's the case, then why am i calibrating my Hanna with growtek 1000ppm reference solution? shouldn't they give you and EC value instead? anyone know what the EC of growtek 1000ppm is or what solute they're using?

is there another brand of TDS meter calibration solution that gives values in EC?

I believe that Hanna uses a .5 conversion, so that would be an EC value of 2.0 at 1000ppm. Why not get a tds meter that doesn't need calibrating? Bluelab ppm pen, Truncheon, or combo meter all are factory calibrated and by far the best meters out there.

Hanna meters are tricky and they like their sauces to calibrate from, which is why a lot of hydro stores stopped carrying them and switched to Bluelab now, forget about ppm, use EC its universal.

1.5EC is 1.5EC in china, america, india, europe, south america and with a milwaukee, bluelab or a hanna.

I tried calibrating with General Hydroponics ppm solution I couldn't even turn the dial to get to the set PPM. I just use the HI7031 solution from hanna now.

I know on my Hanna 115ppm is like .12EC so thats like a 1.0 conversion, no?

Bluelab's calibration solution has it listed:

EC = 2.7
TDS (EC x 500) = 1385
PPM (EC x 700) = 1940

You should use the brand solution that matches your pen or meter. I use Bluelab solution because I have Bluelab pens and meters. I hope that helps.

hope this helps!

Trap Bunkin said:

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hope this helps!

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Thanks. Another generic meter I had read EC around 1.37 at 1000ppm. So did my Hanna. What's that mean?! Both bad probes? Being that the two results converge, i'm not convinced the probes are bad. I'll try calibrating at 2.0 and see what ppm I get.

Also to previous post, I don't see how any probe can be calibration/maintenance free. It might be calibrated out of the box, but it's not going to hold forever.

Anybody have Hanna and grotek 1000ppm solution?

I guess i'm resigned to the fact that no matter what meter you use, it's not going to be 100% accurate. What counts is a precision. As long as my meter reads the same reading for a given concentration each time, ill be ok. I'm pretty confident that Hanna makes a high precision meter, just as i'm sure blue does.

I'm not running high ec anyway. What matters to new is how much my plants are taking in every day, so it's more the difference from day to day i'm interested in.

found the original box for my hanna, which had both EC and ppm calibration solutions. after recalibrating, i tested the Grotek 1000ppm solution and got 1600ppm / EC 2.15 mS! wtf?