what ppm scale should i use? ec x 700 or ec x 500

what ppm scale should i use? ec x 700 or ec x 500??

no one knows?

macwmv said:

what ppm scale should i use? ec x 700 or ec x 500??

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I don't understand your question. What meter are you using? Some meters are calibrated to calculate 500 ppm = 1.0 ec and some calculate 700 ppm = 1.0 ec.