how to calibrate tds meter

[this is me]

just got a new tds meter and there's no instruction written anywhere saying if it's been calibrated or how to calibrate it.
How do I calibrate it? nacl solution with what amount of tds?

 

[nunofs]

There are calibration solutions for TDS meters (usually at 800 or 1600ppm), like this one: http://www.marinedepot.com/md_viewItem.asp?idproduct=RO1353

Nuno

 

[nunofs]

Oh, I should add that calibration is very sensitive to temperature, which to me opens up a whole new can of worms: if you need to know the exact temperature in order to calibrate the TDS meter, how do you calibrate the thermometer in the first place?

Nuno

 

[this is me]

the one I got says that "calibrate with a nacl solution of 342ppm :?
So i'm using the tds meter right out of the box and my RODI is 0 which is pretty normal and my tap water is 103 (?) sounds too clean to me.
and my waste water is at 122.
What you get from your tap water in billerica nuno?

 

[this is me]

Nevermind, just double checked on what it says
"Calibrated with a 342ppm nacl solution"
So i guess its good to go right out of the box.
But still though, can my tap water be 102ppm only? I dont remember the last reading I got from my last meter since I only care to measure the RODI water.

 

[nunofs]

I'm currently getting around 220ppm from the tap... it's gone up as high as 250ppm, and as low as 180ppm before.

Nuno

 

[testhead1313]

For some reason, the brown, nasty water I have here in New Bedford comes in at less than 60 ppm. I thought this was wrong, but it's the second meter I've tried with the same results. I was at a guy's place in Newport who got over 400 out of the tap!

 

[Jim Tansey]

The way we use our meters at or near zero to calibrate at 800 or 1600 is not required and would be done only if accurate measurements were to be made at the higher end of the scale. Calibrating at 800 or 1600 adjusts the full scale point or slope of the curve, since there is no slope at zero adjusting the calibration trimmer at or near zero will have no effect. Check the operation of your meter at zero with distilled water should read zero ( Wallmart $.58 ).

Jim