Need further understanding of EC meter

Hello group. I asked a question about ec meters before, but not sure I fully got it. I get PPM but the other measurement that’s labeled US/CM I do not fully get. I just measured my hydro tank with it and the ppm is about 450 and the US/CM is 1050 or so.

I have a chart of what the PPM should be for different stages if growth but cannot find anything that tells me what the US/CM should be.

Second question is if I wanted to raise the PPM can I do that without raising the US/CM? If so how would I do that. Also vise versa how to I raise the US/CM without raising the PPM?

This is actually µS or milli-siemens (per centimeter) and is not used a lot.

EC means ‘electrical conductivity’ and is one of several scales used for estimating solids in solution.

EC of 1.0 = 500 ppm on the U.S. or NACL scale (salt)
EC of 1.0 = 700 ppm on the U.K./Canada scale (Potassium Chloride)

Each .1 of EC in PPM NACL = 50 ppm

No. It’s a different readout of the same data.


Something is off with your meter. An ec reading of 1.05 and a ppm of 450 doesn’t match up on any scale. Like myfriend stated, it is different ways of reading the same data. Like how you can read temps in Fahrenheit and Celsius.

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