leaves curling up and shriveling on seedlings...any thoughts?

hey all.. new to post, not new to read...

I started some white widows, and the biggest seedling with 3-4 sets of leaves on it has started to turn its leaves up and inward. I dont have pics, sorry, but I have them in rockwool under a 2 ft T5 floures. light. I had them under a clear canopy and removed the canopy last night, and now my biggest grower has turned into my biggest loser!! I cannot imagine that this slight change and under such a minimal light source can cause light burn... am I wrong? Thank you in advance for any help.

have you used any nutrients?

also you said your using a humidity dome?
i never fuck with these; plants have grown for 1000 of years without humidity domes
ive seen someones plants shrivel up within hours of removing the dome

if this is your first grow i would sugest soil over hydro. its easier and more forgiving, while hydro is more expensive and grows faster

I figured out that it was nute burn... I flushed the rockwool with 5.5ph water, waited a few days, and then the plant turned around... it was honestly a bad move on my part to top water with nute solution from the reservoir that my hydro system has in it. I didn't realize that it was at 750 ppm when I scooped. Won't make that mistake again!

take i easy man