Seedling problems; help! (pics included)

I'm running a E+F system and was gone for the weekend, came back to the plants looking like this. I think the lights might have burnt them or they dried out a bit, other thoughts?

rez EC: 405ppm
pH: 5.7
rez temp: 67F
air temp: high 70s
humidity: found it at <20% when I came back home, I think the plants dried out

Im assuming by it being stretched out your using flouro lights? With flouro lights iis almost impossible to burn plants unless they touch the leaves. I would move your light closer, and feed it. Just water it as normal and it should recover in a few days. Also, get that humidity up, For veg, you want a minimum of 45, and a max of 75. But 55-65 is the ideal range.

405 ppm is to much for such a small plant. Feed it with 300ppm. Burned leaftips indicate overfertilizing. A humidity of 20% is far to low! Minimum humidity should be 40%

Yea, my thermo set the heat a bit too high, and in this dry NE weather, the humidity plunged. Seems like my RW is drying out and pulling moisture from the roots/hydroton with it, so I put plastic across the hydroton basket to keep moisture in the root zone, brought the [dissolved solutes] down, and brought the humidity way up.

That's interesting that you noted I'm using fluoro because they're stretched...I'm actually using LED and CFL. Can I expect the plants to continue to stretch, or is that a seedling condition, or what have you found, IHACN?

Small starter system til I learn the ropes, got to start somewhere.

Plants stretch in order to reach a light source. The light of CFL and LED lights does not penetrate as deep as hps/ndl bulbs. To avoid stretch you have to put them very close to your plants.