On-site algae culture is a necessity in most marine hatcheries. Algae is the primary diet for bivalves, larval shrimp and live larval feeds, such as rotifers and Artemia. Many different species of algae are cultured throughout the world and each batch is typically just a single species selected for its size and nutrient profile. During culture, it is crucial that steps are taken to avoid contamination, either from pathogens or from other species of algae or ciliates. Sterilization of all equipment and culture media is, therefore, necessary. They can be autoclaved, dipped in alcohol, chlorinated, etc. Contaminants are often waterborne; however, air can also be a pathway for contamination. Placing the air compressor intake in the culture room or an air-conditioned room reduces temperature fluctuations and contaminant load. Care should also be taken to avoid condensation in the airlines, which can lead to ciliate infestations. Installing an in-line desiccant filter can eliminate condensation. To eliminate a recurring contamination problem, sterilize the air delivery system and use the appropriate inlet air filter.