Got a feeling that algae grow faster on white screen and with a white background the algae is more visible at the beginning.
Though the screen will be fully covered with algae eventually, I believe white surface will help speed up the growth for the first few days after each cleaning.

Finally found an art craft shop that sells white plastic canvas and know what? It is Made in U.S.A.!


The previous black plastic screen was actually meant for covering the drainage holes of flower pot and is harder and stiffer to work with.

Got this from a Japanese budget shop Daiso.

Rough the screen up with a hole saw and this new screen can really be cactus rough. The amount of plastic scrap off is so much more as compared to the black screen.


Seeded the new screen and installed it with a new light shield.