My first hydro experience

pH in hydro should be 5.6 to 5.9, what is yours at?

Dim lights while your plants are wet i mean And make sure the E salt has no lavender r aloe in it. Must be pure ES all pharmacy and major change stores will hv it.

Good spot pal This is very very early signs of mag def..use a foliar spray of epsom salts weekly. 150ppm added to your tap. You can spray your plants right up until pre flower. Going beyond that id just suggest not doing as any mist as much as u try not to will hit the shoots. Also dim your lights a bit. Aswel you could add their general calmag for hydroponics that can be added to the weekly/fortnight change. But get to it. Hydros are fast in moving through signs of anything missing r too much.. A foliar spray will do for now. But find out if your water is hard r soft. I think 200+ is hard water and anything under 180 is counted as soft. But generally these nutes your using come in hard/soft water right? So it'll be best in the long run to add a calmag that is for DWC. Good

look at leaves in normal lighting to judge lushness. they often look paler than they actually are under grow lights. have some chlorosis on new leaves? could be too high p or k... could be low S... more than one thing can cause that visible symptom. refelctin on your fertilization over the last few weeks or month+ can help eliminate possibilities. maybe a bit small for 40 days of vege.. hard to tell in pictures with no point of reference. Whatver imbalance there is, it's only a small factor as it isn't a major issue. genetic variety is the biggest factor for any healthy plant.