Hey GK!
Is it the light that is making all the leaves look so yellow between the veins like that..?!
It looks like it has been creeping up the plants from the older leaves to the top, if the photos are in time sequence..!
That might indicate a magnesium deficiency, that means some cal-mag in the water would help fix!
I hope that it is only the light, but it really does look like they are turning yellow, my dude!