I just changed the light schedule. Until today they were on 24 and now they will be on 18/6.
They were suffering from 3 conditions.
Temp and humidity: The temps are way to high even at night, I put a ventilator inside to help and raised the humidity by not removing the runoff.
Light: The light was too close and too intense to the seedlings, I raised it lowering the PPFD to 160.
Nutrients: I was supposed to feed them at the very first watering but I didn't. Today I started feeding them and they seem to love it. I could spot the difference in the leave color after a few hours.