Seedlings 3 weeks old - What's wrong here?

Seed starter soil, 24/0 under CFL lights, Distilled water, 70-80 degrees but can only manage 36% humidity. Am I over watering, need Nutes? This is the worst of the bunch. Noticed several others, not yellow but a lighter green than they were and some are starting to show similar browning as this photo. Thanks in advance for your help - Rhody420 !!!!!!!

Well lets see. What kind of seed soil are you using and where did you get it from? You're temperature is OK and lightning is OK. I'd say allow your humidity to raise a little since babies do enjoy that. What's the Ph of the distilled water that you are using and does it have any added ingredients? I'd switch over to your average tap water for your next few feedings. Its Ph is normally.around 7-7.2.. here to help hopefully you can provide a little bit more info

Going thru some of my personal grow journals in think your problem may be one of the three. First-Chlorine deficiency 2nd-Copper deficiency 3rd-zinc deficiency . Chlorine can be fixed by simple giving it tap/faucet water. Copper can be corrected by adding a simple copper based sulfate. Don't apply if temps are over 75°f(24°c) but this seldom that plants need it. Zinc can be corrected by flushing your soil with a mix that contains trace elements of zinc,iron, and manganese. Do a little research on each before you act. I hope this helps out.

If that's three weeks it might be time to let it go.

Its 100 percent to do with the roots, did you put into soil straight away? Let the roots develop first if your soil has fertz in if not then you have fed it to much nutes to early!