Glad to hear that your baby is doing better. RE: your question 1. There are a string of posts started by Bobbie on 2/2/00 re: NaCl that talk about salt supplements for infants. They should give you lots of good info. I can't help on this topic. My son never had salt supplements. He was breastfed and on 1 1/2 tablets of florinef and his sodium and potassium levels were good. Now he is on one tablet of florinef and we heavily salt his table food. I guess we have been very lucky. He seems to not be a severe salt waster at this point. re: question 2. If your baby's soft spot on the top of her head is sunken this sounds like dehydration. I am not a dr. so I hate to go too far into advice, but I was told that "water follows salt" so if your daughter is losing a lot of salt, she might be losing alot of water as well and become dehydrated. I know my son drinks TONS of water and liquid every day. Since he was about 6 months old I have kept spill proof water glasses all around the house and he constantly drinks from them. Hopefully someone else will respond also about dehydration. Wishing your family good luck!