Don't know about the cycling aspect but...
Brown Algae (Diatoms) — This is the first type of algae that begins growing in a new aquarium. It usually grows on the gravel and glass. Unlike other types of algae, this type requires silicates in order to grow. By increasing light levels, this type of algae can be replaced by the more beneficial green algae. Brown algae can easily be scraped off the glass. Herbivorous African cichlids generally have little to no interest in this type of algae as an easy meal.
Taken from cichlid-forum library.