Drooping Leaves, Spotting- Hydro....I searched...pics

[routter]

Hi and thanks for the time. First time hydro grow here.

DWC
Problem w/ g13/haze
21 days veg from clone
1000w mh @ 12"
Lucas Formula
ph 6.2
ppm 590 @ .5
room temp 68-84
5x4x8 room, cool tube, reasonable facsilmile of Rumple's


So- after a rocky start- blown res temps etc...the girls are starting to move. The first two pics are the g/haze. She's, as can be seen, been going gangbusters compared to the others. But now, I'm finding some droop and spotting on older leaves.

I had the start of some root rot on the NL #5 plants (last two pics) due to poor res temps, but none w/ the G. Nonetheless, I added 35% h2o2 at the proper proportions this week, along w/ some hygrozyme to all plants.

Around this time she started her droop while the NL's took off. Temps also went lower in the eve's (high 60's) at the same time.

Temp issues will be a thing of the past in the next coupla days as the room as A/C and and aquarium chiller will be added to the mix to enable co2 enrichment.

So- what's my problem? Temps? H2o2 shock? Stupidity?