The commercial media that is commonly used also contains a buffer to help maintain pH, and a pH indicating dye. If your medium goes from being light pink, to very bright pink, then not enough CO2 is present. Some researchers do not believe in adding these antimicrobials, as they could influence cell behavior. Glutamine is a vital nutrient, which is added prior to use because of its tendency to break down. Trypsin is used to break the bonds that the cells have formed with the plastic, so that the cells can be removed and split into new containers.
Many types are available, as mentioned above.
A column of air assists in keeping microbes out and filters outgoing air. Do NOT let your plasticware, cells, etc, extend into the blowing region near the front of the hood. Can regulate the amount of CO2 and humidity the cells experience. Usually 5 to 10 percent. Means of Disposal- Bleach for liquids, and autoclaving for solids and plastics.