So I made the decision to think in Ec as most of the top botanists think on this scale as it is universal. There are 3 ppm scales I'm aware of 500 650 and 700 so you have to translate what a ppm dude may be attempting to say and most aren't aware of what their meter is even calibrated to so massive swing in actual readings. At 1.2 Ec you can feed perpetually as a flush from higher Ec levels brings you back to the beginning. I found the minerals are Marshalled past the casperian strip easier allowing for continual easy feeding. Amino acids and kelp at a 5:2 ratio increase biochemical reactions 50% in the rhyzosphere. Hope that helps.