I have "NiteOut II" used in conjunction with "Special Blend" of the same brand, as has been set in my marine aquarium by a nutrient limitation unfavorable Bakterieneverhältnis. It could grow red cyano-bacteria, which have replaced the already weak population of beneficial bacteria. With the combination of Special Blend and NiteOut II (and remove the cyano-coverings) I was able to push back the cyano-bacteria and restore a healthy bacterial environment.