That last pic is CLASSIC nitrogen toxicity. Look at the dull leaf surfaces and very deep rich intense green color.

The low yellowing and the splotches on it look to me like a combination of a couple things- less light penetrating the canopy (main problem with flourescent grows) plus you seem to have a calcium lockout that's getting fairly bad.

You've gotta get that soil to dry out better between waterings and keep up with your calmag. I would feed with just plain tap water and calmag for now, and give a light foliar (concentrating on lower growth) with your micronutrient at a concentration weaker than the bottle recommends. Try to let it dry out pretty well before shutting the door.

Neat cabinet btw!

Oh. Stretch. Next time, stick the pots up on something to get them closer to the lights while they are still young so that you can keep them short and fat. I see your nodes are close together though, and the apparent 'stretch' may simply be an illusion caused by the number of lower nodes that have already dropped their leaves.