Hi @Marijuana_dan ,
I noticed something yesterday that could explain the difference: that plant looked to be the closest one to your fan.
The extra air speed causes the plant to dry out a little faster. That means the plant will uptake water and therefore nutrients a little faster (VPD).
So I think she may have just used up the available nutrients a little faster than the others. At the 4 week mark, you can probably expect them all to be getting hungry soon.
You mentioned that you had some bottled nutes - I’ve never used those myself, besides the CalMag that I use to buffer my coco coir. It’s a 1-0-0 and I’ve used it a couple times when I’ve noticed a slight N deficiency, like you’re seeing there.
But I’ll also top dress with worm castings and the organic dry amendments I use for my feeding regiment (Down to Earth 4-4-4 and 4-8-4).