One day, as they frequently do, the oyster hatchery team changed the water in the tanks containing oyster larvae. Armed with that information, Harvey obtained additional data from the Phytoplankton Monitoring Network, a group of UGA Marine Extension and Georgia Sea Grant volunteers who collect and monitor water samples from the Skidaway River for phytoplankton and harmful algal blooms on a weekly basis. Harvey and Bliss are fairly certain they have found the source of the problem, but they are still unclear how the algae are harming the oyster larvae, and, more importantly, how to prevent it in the future.