these guys I put on the right side with the 400 watt HPS bulb..

Over the last 36 hours they have gotten ugly.

The stems and leaves feel solid and not flimsey. they feel sorta dry though..Maybe humidity is low?

I'm reading this may be a nitrogen deficiency also also looks like a overage of nito too.. the stemes are turning purple or red.
I changed the reservoir and add 2 gallons of water with 4mls of GH grow, mico and bloom each. and thats about 6-7-10 but only a quarter of the strength..

let them suck that up for 2 hours and then took em outta the water incase they are over hydrated.. will leave them outta the water till morning and in dark for 6 hours.. 18/6 cycle

Here are some pics of the sick ones..