Why do I see the occasional algae layer on my soil media and what does it mean?

Algae on soil surfaces represent no issues unless it becomes thick (2-5mm). Once it gets thicker than 5mm, it may impact soil gas exchange, though it is highly unlikely. Algae growth on the soil surface is typical and found on all soil surfaces exposed to adequate light sources. The exception being plants grown entirely in aseptic environments (they would exhibit no algae growth).

Algae on soil surface causes no pathological response to plants. It may be a source of carbon/carbohydrates for fungus gnats but with silica present, in the Harvest Hero, it becomes a non-issue. There is actually a positive symbiotic relationship between the plant, the roots, and the surface algae, and it is just another component of a healthy soil ecosystem.