Raphidocelis subcapitata, a freshwater alga widely used in environmental testing, shows synchronized growth and budding under light exposure. CASY provides precise, real-time quantification of this process. With a cell size of ~6 µm, each mother cell produces four daughter cells. As budding begins, daughter cells emerge and increase over a 4–5 hour window while mother cells nearly disappear - patterns that CASY accurately tracks.