They look hungry to me. I would raise the EC/PPM.
I'm assuming your growing hydro, I seen your old sig, and plants look like they are in rockwool... main thing is checking pH twice a day until you know how it fluctuates. Then know whether to change res or adjust pH.
I have never used rockwool and hydrocorn together cause the CEC (CATION EXCHANGE CAPACITY) of those are different. Hydrocorn has a neutral pH and works great alone, but rockwool requires nuts a slightly lower pH for optimal nutrient uptake.