Recipes for this medium vary with respect to the amount of V8 juice added. Some use one 6 oz. can (180 ml/liter) because it is convenient.
The calcium carbonate is reported to prevent the acidity of the juice from hydrolyzing the agar.
Rob Wick reports no problems with solidification when CaCO3 was lacking.
This medium is often used to grow Pythium and Phytophthora.
If it is important to view microscopic features directly on the medium, it should be clarified by filtration or centrifugation before sterilization.