Treatment:
Compsopogon and Audouinella ("staghorn" and "black beard/brush algae"): Solving red algae usually requires time - often two to three weeks before it begins to change for the better. What definitely does not work on red algae is the tank blackout (or reduction of photoperiod) → this is only logical as red algae can grow even under very low lighting conditions (5 �mol PAR). What helps on the other hand, is the local application of glutaraldehyde (Excel or EasyCarbo), although this only solves the effects, not the cause. It may also help to do more frequent water changes and/or reduce the light intensity with slight shading by floating plants. Anyway, no method will work until you first do not solve the problem with CO2. CO2 constitute 40-45% of the plant biomass and can dramatically affect the reception of any additional nutrient (all other nutrients needed carbon to allow them to be converted into organic form digestible for plants → no carbon = no nutrients = no growth). Algae can not be easily mechanically removed (perhaps only by scraping with a sharp object). Seriously infested leaves and plant parts should be thoroughly removed in order to prevent the algae from spreading. Among the animals that feed on this algae (but only if hungry!) is Siamese algae-eater (SAE) or Yamato shrimp. The most effective method to control the growth of algae is to ensure unlimiting and stable levels of CO2, adequate lighting, and enough nutrients in combination with good care for aquarium and aquatic plants. High concentrations of CO2 (e.g. about 100 ppm) will not destroy this algae by itself (and presumably not even suppress its growth). Good and stable levels of CO2, however, can help to prevent the overgrowth of this algae. However, the best defense against its spread is large number of plants. If we want for our aquarium to flourish, it is essential for us to focus primarily on the growth and well-being of plants, which should never play a subordinate role in our aquariums. Failure to comply with this rule is usually the most common cause of problems with algae.
