What you think about these spots?

As the thread title suggests, I am wondering if anyone cares to take a shot at diagnosing these spots. (foliage in photos appear more yellow than in person, in real life plants appear mostly healthy)

they are entering week 5 under two PL-L55 lamps, nutes are at 1500ppm (water w/o nutes come up @210) using Lucas formula w/ GH Micro+Bloom in rockwool handwatered, PH is/should be 6.0 it ran a bit high this past week and I flushed till run off was 5.8 right before I took the pic above (pics below are 2 weeks ago and then todays)

Nute burn baby. Ease off on that PPM.

I should know, I did the same thing to my plants recently... only I burned mine with only 600PPM.

Pretty plants btw.

thanks for the reply, ill cut it back next time i feed