Conversion rate for my TDS meter

[clowntown]

 

[BlindDate]

Go to the hydro shop and buy some KNOWN cal solution and you will know for sure.

 

[mtnjohn]

hey CT

i contacted HM digital about this very subject and this is what i rec'd

Thank you for your interest in our products. Our TDS-3 uses the NaCl conversion factor, which averages at 0.5 of EC.



However, the COM-100 http://tdsmeter.com/products/com100.html has true conversion factors for NaCl as well as 442( average is 0.7 of EC). It also measures in EC.



Regards,

Charles Lee

General Manager



HM Digital, Inc.

5819 Uplander Way
Culver City , CA 90230 USA

so....there you have it bro...straight from the horses mouth

mj

 

[blynx]

So if your TDS3 meter reads 170ppm, then your EC is 340?

 

[Guest]

Go to the hydro shop and buy some KNOWN cal solution and you will know for sure.

Couldn't agree more. You need some calibration solution anyway.

 

[Guest]

So if your TDS3 meter reads 170ppm, then your EC is 340?

Yes...that's what it should be.

Clowntown...I highly doubt your cheapo meter has an adjustable ratio. Mine does but I ignore the ppm feature as it's useless.

 

[clowntown]

Wow mtnjohn, you're !@#$ing awesome for going out of your way to find that for me! Thanks to everyone else for the input as well!

With that information, I can now easily rely on using the "Hanna conversion" for the nute readings and EC conversions!

 

[Guest]

I contacted them also, because I was under the assumption that they used a .7 conversion...but it turns out it's .5 So...now I know why I was over feeding. Having ppm's in the 1400 range and sometimes even higher was an Ec of about 2.5 and higher. Yikes!!

Cheers,
SH

 

[ItsGrowTime]

I think the NaCl reference also means a .5 conversion rate. Its a different cal fluid if its .7.

 

[clowntown]

Clowntown...I highly doubt your cheapo meter has an adjustable ratio. Mine does but I ignore the ppm feature as it's useless.

Didn't say adjustable... variable... meaning that at different EC's a different ratio is applied. For example at 0.0 - 0.9 EC, a conversion ratio of .6 and at an EC of 1.0 - 2.0 a conversion ratio of 0.5 or something. That's what it was starting to sound like.

 

[clowntown]

http://www.icmag.com/ic/showthread.php?t=57971

 

[Guest]

I understand what you're saying but this ppm talk is a waste of time IMO. A meter reads ec then converts to ppm's and different manufacturers, for whatever reason, use different conversion factors. I can adjust my Hanna 991404 continuous monitor meter to provide a different ppm reading on the display but no matter what the ppm reading/display is the ec is always the same so I just don't bother with ppm. I only care about ec cause no matter what meter you're using ec is always the same.

 

[clowntown]

I don't think you're getting what I'm trying to say, so: I have a TDS meter. I don't care for PPM readings anymore really, just the EC readings. But I didn't know what the EC value is because I didn't know what number to use to convert the PPM that my meter displays. Now that I know, I can start talking EC instead of PPM without a new meter.

 

[BlindDate]

Looks like its the .5 conversion but I would sure as hell get some cal solution and test.

 

[mtnjohn]

Looks like its the .5 conversion but I would sure as hell get some cal solution and test.

i'm pretty sure the manufacturer has a pretty good idea of what conversion rate their meter is

that being said...having test/cal. solutions are a must

mj

 

[blynx]

So if your TDS3 meter reads 170ppm, then your EC is 340?

I was still a bit confused, but I found it easier to think of it this way.

To find your EC from a TDS3 PPM reading, you take the PPM reading and divide by 500.

If you get a 170 PPM reading, your EC = 170/500 = .34