zoo med calcium without vitamin d3 reptile food, 3-ounce (4 pack) zoo med 4 pack of zoo med calcium without vitamin d3 reptile food, 3-ounce each. repti calcium is an ultra fine precipitated calcium carbonate supplement. it is a phosphorus-free calcium supplement for reptiles and amphibians. it has a unique shape/high surface area per gram resulting in increased calcium bioavailability.