Deficiency, Burn, PH???

AK-47 clones were planted 11 days ago. They are all from the same Mommy. PH is 5.8, and the EC is 1.50.
They are in an Aeroflo system on a 12/12. Temps are a comfy 74 degrees, and slightly warmer right next to the bulb, 600 HPS.
I use GH Flora, and stick pretty much to the game plan outlined by GH.

Is it possible that this could be related to having low levels of CO2? I have a large, but enclosed/sealed area for my room, and just started supplementing with CO2 yesterday.

Almost looks like mite damage.

I think I may have found the problem:
View attachment 1107951
Actually, I found this little guy right outside the room. It's probably a bigger danger to me than the plants, but I think I'll still kill it.

haha killl that fucker how did he get there

It must be the season for them. That's the 4th one I've found in the house this month. But the other ones were tiny compared to this one. I have no idea how they get in, and regular insect spray doesn't even phase them.