I recently got a PPM meter that checks EC CF and PPM (700 scale) and TDS calibration solution that is 342 and 1000 ppm. (I am pretty sure it converts to 700 scale. I am at .86 EC currently and 600 ppm.) The solution does not actually say what PPM scale it is on, but says NaCl on it which makes me think it is calibration solution for a 500 scale ppm meter. So my question is what is the EC (Cause I can calibrate that) of NaCl TDS calibration solution 342 ppm and 1000 ppm? The 1000 should be an EC of 2.0 right? I am going to get a blue lab monitor for my res but want to get this straight while I wait for it. This is the calibration solution I am using https://www.amazon.com/HM-Digital-C342-Calibration-Solution/dp/B001VE99X8/ref=asc_df_B001VE99X8/?tag=hyprod-20&linkCode=df0&hvadid=167138399519&hvpos=&hvnetw=g&hvrand=12830387075903049010&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1026748&hvtargid=pla-307836974550&psc=1