For several years, microalgae have been an important source of nutritional products, fuel alternatives, and chemicals. The research into these types of algae for foods, pharmaceuticals, and other chemicals is quickly growing due to the importance of finding more sustainable and less expensive means to produce these products. Depending upon the species, microalgae can be grown in open raceways, photobioreactors, or fermenters. Regardless of the production systems, the maintenance of a healthy culture and the ability to monitor that culture is essential. Flow cytometry is an ideal tool for investigating and monitoring algal cultures. In general, strain improvement in microalgae requires the ability to screen several strains for potential improvement in the target product. The Invitrogen Attune NxT Flow Cytometer offers superior speed and the ability to handle the large and adherent forms of algal culture. In addition, the acoustic focusing technology and Attune NxT Auto Sampler allow for high- throughput screening of strains for improved phenotying and minimal clogging.