Problem still exists? or is it healing now? How can u tell?

I Don't know whats wrong....

One of my plants has it bad, it lost like 5 fan leaves attactched to the main stem.. but the other leaves are ok...

And on one of my other plants... one fan leaf is actually 50% yellow/brown, and 50% perfect...Straight down the middle of the leaf vein.

Homemade aero setup... (no light leaks, good spray, and ventilated, cool water)
600watt hps...
5.7ph
700PPM of nutes.. botanicare grow...
few drops of superthrive..
and some botanicare Sweet...
temps at 74-77
and humidity at 45-55%

Are they fine now????

doesnt look like nute burn
maybe it is a lack of some element???
potasium or co2

Ok, well i changed the water, and used GH 3 part nutes now, and it looks like all of them picked up right away, and are growing EXCEPT ONE...

It is really drooped, and almost looks dead, but its not.

The roots get sprayed with water, and no light gets to the roots.

What could be the problem!? Its been 2 days and its like this. You can see in the pictures, the one to the very right corner closest to you.

aghh... no one ever helps.....