Blue-green algae can multiply quickly in nutrient-rich environments. The study was carried out to determine the appropriate medium and nutrient content for the growth of Microcystis sp. The study consisted of two experiments conducted in an indoor hatchery. Microcystis sp. algae was cultured in 8-liter plastic bottles with a light intensity of 3,000 Lux using white LED light and an aeration time of 24/24 hours. In experiment 1, Microcystis sp. was separately cultured in different mediums, namely BG11, Zarrouk, and NPK (16:16:8). Each treatment was repeated three times. The results indicated that the density of Microcystis sp. was the highest in the NPK treatment (16.2×106 cells mL-1 ). In addition, dry weight (58.02 g L -1 ) and chlorophyll-a content (4,054 µg L -1 ) in the NPK treatment had higher densities than other mediums after 8 days of culture. For the experiment 2, when using NPK cultured at doses of 50, 75, 100, and 150 mg L -1 , the results showed that the algal abundance was the highest (14.5×106 cells mL-1 ) in the 50 mg L -1 dose after 10 days of culture. In summary, inorganic fertilizer NPK at a concentration of 50 mg L -1 can be used effectively in the mass cultivation of Microcystis sp. microalgae.