m0useanswered grow question 2 months ago EC and PPM are one if the same. Don't need both figures. EC is more universal so better to use it.
Eg.
1EC=1EC globally.
However 1EC could = 500ppm or 650ppm or 700ppm depending on where you are globally. Its just measuring its conductivity in the liquid and is not 100% representative of the total dissolved solids "TDS" as sugar dissolves in water but does not affect the EC/PPM of any meter as it is not conductive.
A 1.6EC = 800PPM means you are useing the 500 Scale. its common in north america.
If you runoff is to high, it could be a few things.
1) you are feeding to much and need to cut it back a bit
2) you are measuring the runoff incorrectly and getting a false elevated number
3) you need more runoff
3.5) your pens need calibration.
Measure your runoff after the first bit of piss comes out of the pot. The first bit is always higher, and if you let it sit in the tray it will also have dried salts that will artificially elevate the numbers. Water slowly and not too fast, Also can use a wetting agent like Yucca to help it flush out and avoid dry spots. but it works best watering a bit then waiting and watering some more. Give it time to work. but that's only if you suspect you have dry spots fucking you up.