I'm at 1.7mS (850ppm) for veg and that's what I keep it at for flower. I'm still sorting things out--last grow I had my LEDs too close and the top of the plants were sunburnt but the understory was perfect.
The plants for the current grow are at one month of veg and the newer growth is looking good but more lime green than I think it should be. I did a grow starting with
MaxiGro and I liked the early look of things better with that, I wonder if I'm giving enough N with the standard Jack's ratio (1.67:1 or 1.5:1, Jack's Pro to Cal-Nit, plus Epsom and Drip Clean). I'm a ways from getting things dialed in, been fighting unusually high temps in my Seattle basement for over a month.
I recently started adding
Pro-tekt as a supplement but only at 1ml per gallon. The setup is
Blumat drip-coco-fabric pots.
If you could post a photo of your plants someone will probably have more informed advice.