Iodine for my children

Hi everyone.
I'm new to this forum and was hoping someone could help me out here! I have been looking everywhere online but can't seem to find the answer! So I thought I'd just ask in a forum. Can anyone tell me where can buy Iodine supplements for my small children? What is the brad name, what type is the safest? Are tablets or liquid better? Anyone supplements their children? What do you use? And are you sure its safe? Before learning of the DANGERS of fluoride, I bottle fed my son for 6 months with fluoridated water and I remember my daughter accidentally ate toothpaste a bunch of times when she was younger. and recently ate some deodorant. And all the cap I have been unknowingly feeding them in their food etc, I just want all this cap out of their bodies and I want them to be protected from it cuz its everywhere and I know it is detrimental to their brain development! Any help would be greatly appreciated cuz I am nervous to give them iodine, as I still don't know too much about it and I know too much is not good for them. My daughter is 2 1/2 and my son is almost 1 1/2. I also have a baby on the way, when can I start giving her iodine? Thanks for your time and help!