what else could it be? i was gone for 8 days and the res ran bone dry, im sure the tds level became sky high as it got lower, i set the12/12 before i left and they stretched a foot at least, the roots are brown, im using 1/4 nute and hygrozyme,
I have to ask so for my own amusement. Why would you leave your plants alone for longer than the res can handle? You've been growing them all along, you know how much they drink.
Why would you set them to 12/12 right before you leave? This means you changed their nutrients. You should be wathcing VERY closely during the first week of 12/12.
How could you have possibly set your lights properly. The lights need to start going up inches every day.
Why take all that time vegging those plants, then set the timer to 12/12 and leave? You were much better off to leave them in veg the week you were gone. Same old nutrients they've been happy with and no crazy stretching. If the power went out or the pump died you would have the same results. There were a million ways for this to end this way, it's not "bad luck".
But you live, you learn and sometimes you don't have a choice in the matter, but there were ways to at least try to mitigate this.
It definitely looks like they died from growing into the lights and having no water. Said no water had no nutrients so the plant is hopelessly stressed out. I really think it's going to take longer to try to fix these stressed out, probably hermied plants. They are potentially crippled in the yield department as well IF they ever really recovered and were viable.
I would call it and start over as a matter of eficiency. You aren't SAVING any time at this point. You could waste 4 weeks trying to get them back up to snuff. In the meantime you could've done better things.