For the future, don't pay mind to what the manufacturers say about their coco...you should wash it and re-buffer it yourself. This way you know exactly where you're starting from vs. assuming what the manufacture is telling you is true. Many times things are said in order to make a sale. At this point in your plant's lives, if you're seeing any sort of issue it's most likely pH related. That little seedling isn't pulling enough of anything to be considered deficient. I don't know where 200 ppm lies in terms of your feed program, but in my experience, I start off with a 25% feed solution, from day 1 and then make my future adjustments based on what the plants are telling me. Try to be patient and let them grow a little, keeping in mind pH. Let us know how things go over the next week or so. Oh, and don't let your coco dry out...it should always retain some moisture or you're going to experience issues.
