Is this Ca deficiency or something else?

[Spaceboy79]

Hi
I am new to growing (3 grows) and I run a 4 pot DWC system in which I currently have 2 small Auto Flowers (I know I must go fem, just using the last Auto seeds) - I used the Lucas method at 1/2 strength (5/10) - these seedlings is roughly 2 1/2 weeks old and this looks like a Ca deficiency to me, but I would like confirmation before I add some Ca/Mg and worsen the problem.
Regards in advance

 

[Badchoice]

Keep this as a reference

 

[Spaceboy79]

Keep this as a reference

I do have that chart, but thanks a million for it - I actually just wanted to get confirmation if my “diagnosis” is right or alternatively wrong

 

[Badchoice]

Still kind of early but it looks like a lack of cal-mag if the yellow spreads more than it’s nitrogen.

 

[Spaceboy79]

Still kind of early but it looks like a lack of cal-mag if the yellow spreads more than it’s nitrogen.

Thank you for the help