It may be safe at that level in the short term but there is research indicating possible toxic effects(neurological)on small children over 1 part per million in drinking water. It's not only about weight. I'm not sure what the best alternative would be for children, perhaps coconut oil if they would take it or a small amount of Iodine supplementation or Colloidal Silver . There are forums for all these. If you read what I said about candida in the thread above I don't think Miracle-Mineral-Supplement is the best for it though it may work for some.
Diet is critical as regards Sugar etc and avoiding non essential Antibiotic use of course.
The question is how the candida becomes a problem and preventing this in future