Hi there el1816, looks like you have pretty serious nutrient burn on the seedlings. At this stage , in soil, you shouldnt be feeding anything except plain water. When you added the nutrients it caused lock outs and your plant is now showing stress and burn. So what you should do, is assure you are following a very strict wet/dry cycle, but only water with plain water until week 3 at least and then you should follow a very strict "feed water water feed water water feed water water" schedule to make sure this doesnt happen again. Hope this helps El ! 🚀