[Plant-education] duckweed,lemna gibba unable to grow

[mak]

hi guys thank you in advance .
i am starting a research on duckweeds to treat wastewater,the problem
lies in that the plants are dying before i start the work i have tried
sugar to grow and multiply the plants and also some other stuffs pls
suggest your ideas how to multiply and grow this plants efficiently
and do my treatment.
thx