Plankton is an important organism for other living things. Especially, phytoplankton contains pigment in cells, can absorb light energy and use in the process of photosynthesis and provide organic matter. Phytoplankton is the primary producer of the food chain and food web, being food for zooplankton, aquatic larvae and aquatic animal; as well as being utilized by humans in the breeding and nursing of aquatic animal. Therefore, the light factor is very important for phytoplankton photosynthesis.

      Study on ten types of different light wave length of white light Fluorescent bulbs (Color Temperature 6,500 K), white LED bulbs (Color Temperature 6,500 K), white LED bulbs (Color Temperature 15,000 K), warm white LED bulbs(Color Temperature 3,200 K),  Infrared LED bulbs (730-740 nm), red LED bulbs (620-625 nm), Orange LED bulbs (590-595 nm), Green LED bulbs (520-525 nm), Red LED bulbs (620-625 nm), Blue LED bulbs (460-465 nm) and UV LED bulbs (520-525 nm) in cultured of Chlorella (Chlorella sp.) cultured under laboratory conditions (25ºC temperature-controlled room). Cell samples were collected every 24 hours for 10 days.  At the end of the experiment showed that light from the Blue LED bulbs (460-465 nm) can increase the maximum number of cells with the average of growth rate 0.69±0.12x10⁶ cells/day followed by the second White LED bulbs (Color Temperature 15,000 K) cells averaged 0.65±0.11x10⁶ cells/day and the third sequence, Red LED bulbs (620-625 nm) cells averaged 0.62 ±0.38x10⁶ cells/day, respectively.