Your call, leaves that light I add nutes leaves darker than that I bring them down. My EC is just a guideline that I use for determining how much food my plants are eating rather than the concentration.
I would up the grow feed slightly. Very gradually and watch for burnt tips. I tend to learn a strain by finding out how hot it can run then lowering slightly. That only really works if you have multiple runs of the same stain.
All the information here is from my head. Please verify it yourself before acting as I dont grow hydro
Mouse