Cyanobacteria, the purple slime that invades the sand and live rock of marine aquariums, is one of those enigmatic nuisance organisms that thrives on excess organic compounds and light energy, but doesn’t necessarily vanish if those sources are taken away. The slime can seem to disappear, only to reappear in full force within a matter of hours, often causing hobbyists to pull their hair out in frustration. To fully remove the cyano takes dedication. Water changes alone won’t solve the problem. The hobbyist must manually remove the slime, as well as add to the filtration (carbon and live bacteria for example), and potentially even turn the lights out for a few days. Improved water flow in the area where the cyanobacteria is growing is another popular method.