What is going on here? 1 of 6 plants look weird

What is wrong with this plant?

As you can see in the second photo, 1 out of 6 is doing really bad. (And the one next to it, in the back, is thirsty).

I suspect something is wrong with the irrigation lines, but I am not sure.

I have plenty (4) lines to each pot. Therefore I am not really sure what the issue is.

The leaf drooping (all plants) looks like classic overwatering.

For one thing too much nitrogen and I agree with overwatering as well.

I think it is under watering. I am not running soil, this is soilless with peat/vermiculite 50/50. It can be watered loads without and oxygen problem.

I think the plants furthest from the irrigation pump are getting much less water than the other ones. This is causing salt build up and burning.

Sound about right????

I had this same issue. I figured it was boron def. I flushed, started feeding heavier at a little lower ph, and more frequently. Power Si helped them recover quickly. They completely recovered.