stem went from white to brown/purple

OF is hot AF.. so don't fertilize. simply water.. don't de-chlorinate unless you have unusually high levels, otherwise the ppms in tap water are generalyl nothing but a good thing for the plant. stick to wet-dry cycle. top 1" dry before waterign again... you have a small plant in a big pot, so that is more difficut, but doable. simply water in ~4-6" radius around it, hydrate the edges less, but don't let them get bone-dry to save a hassle later. Increase radius of watering as plant grows... If anything it's a toxicity/lockout due to soil or too dry of soil in the vicinity. can't be a deficiency that early. No worries, it will survive. it will be fruitful :P