It's been a good week as far as seedlings go. I had it to close to the light at first but I caught it fast and it seem to recover. I'll keep her happy and healthy for now she has more to come.
she is heavily underfed or even overwatered with wrong pH
for coco in veg its 5.8-6.0 and in flower 6.0-6.2
in coco you have to feed, your medium is empty.
havent used your line, but she is not happy for sure .
Rethink.
Happy Growing !