This is the very same agar mixture that we use for our pre-poured plates both PDYA & Carbon. 300G will make 3-400 plates, depending on fill volume. We use 15ML/100MM plate, your mileage may vary depending on how you pour. Recommended use 30G/1000ML water. More for a firmer media, less for a softer media. Softer media is sometimes desirable for work with spores. After opening, refrigeration is recommended for all pre-mixed agar, refrigeration REQUIRED for antibiotic agar after opening. Comes in a sealed, resealable bag. NOT FOR HUMAN OR ANIMAL CONSUMPTION!!!