I started adding fertilizier this week and got the humidity and pH inside the desired range. I don't know why the leaves are still a little pale nevertheless. I'm not sure if it could be a small amount of light stress? In any case, I've decreased the DLI from around 25 to 20 for next week.
Day 12 / Feb 7:
Watered
Day 14 / Feb 9:
Watered
Day 17 / Feb 12:
Watered