Gardeners can do away with algae and ruin the fun for fungus gnats with
the pesticide-free Cubecap. The Cubecap rests on top of a coco or
rockwool cube and reflects light back up to the plant, preventing it
from reaching the places algae likes to grow. Its unique shape also
promotes airflow around the top of the growing medium, allowing
moisture to evaporate. With no moisture and no light, algae can’t grow,
and fungus gnats will disappear when the algae are gone. 4” Cubecap
fits all 4” rockwool and coco fiber cubes.