1,000 mg of Calcium should not be a problem for the Dr. Brownstein Iodine Protocol.
Sorry but I am extremely skeptical of liver & kidney flushes. So I am not the person to ask. I say that the liver & kidneys know how to flush themselves if given a decent Paleo Diet. There are forums at the curezone for liver & kidney flushes that will be happy to get you on the bandwagon. IMO a clean Paleo Diet with distilled or mineral water is the best way for clean organs. Vitamin C should be taken to bowel tolerance for best results. The best is Sodium Ascorbic or Ascorbic Acid.