Niceeee Sanchez, got yourself a little ppfd metreeee.
Reduce to 150-200 at most at 20 hours. Until at least she gets 3-5 internodes then up it. 400 at 20 is too much for wee baby, may stunt.him a little.
20 hours in seconds.
60x60x20= 72000 seconds in 20 hours.
72000x400=28,800,000 micromoles.
28.8dli
Ease off a little, right now your feeding too much for a little seedling, once she has 3,4,5 internodes then you can apply a dli closer to 35-40.
If your maxing out the dli though remember you need to gear up the water cycle to match or you will bottleneck growth.
72