Your ppm meter doesnâ??t know squat about ppm. It only makes an approximation at ppm by measuring EC (electrical conductivity).
It then takes itâ??s EC figure and converts that to ppm with a factor of .5 or .7 to estimate ppm.
Note: EC is exactly the same on all meters. (itâ??s a baseline to work from)

So if you want to communicate ppm then you have to consider the conversion factor.
Example:
EC= 2100
2100 X .7 = 1470
2100 X .5 + 1050 Two very different conclusions.
So if anybody posts ppm without including their conversion factor, well then you have nothing to work with (to compare).

Letâ??s say that your meter converts at .7 and another posts ppm at a .5 conversion factor. Then you have to take (their ppm) X (the recriprocal of .5 (2.0)) to learn the EC of their solution.
Example:
Ppm 1050 (@.5) X 2 = 2100
2100 x .7 = 1470
So their 1050 ppm @.5 equals 1470 ppm @ .7 to you
If the situation was reversedâ?¦.the reciprocal of .7 is 1.4285

To find the conversion factor of your meter (if you have an EC function) Simply measure any solution for ECâ?¦then measure for ppm to see which conversion factor it uses. If not check the instructions.

My meter allows either conversion factor (I choose) I chose .7 because it seems to be a little more commonly used.

Let me know if this helps
HMR
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