Hi again! I'm sure you guys are all getting tired of me but here I am again. I recently joined the MAGIC group and got my networking info today. What is the difference beteween the 17 H and the 21 H? How do I know which one my daughter has? I do know that she is salt wasting. I am so hungry for knowledge and trying to understand all of this I can hardly stand it. Also, if anyone knows of any good publications out there PLEASE let me know!