Do away with algae and ruin the fun for fungus gnats with the pesticide-free Cubecap. It 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. Fits all 4" rockwool and coco fiber cubes.