I had a bit of green slime( maybe some brown too) showing up in my aquarium for the past couple of months. At first I was thinking it was algae as it was rather bright green. But my nutrients were very low so I was perplexed. Turns out it was cyano or some sort of green sludge. I wish I had known/identified it a little earlier as my setosa suffered some skin loss. A few other corals lost color. I think as the cyano free floats it irritates the corals until there's a bare spot exposing the skeleton and then it takes hold on that coral. The green slime covers sand just like red cyano. The product seems to be marketed toward red cyano but works on other types and also could be used as a regular maintenance product. It did not hurt any of my corals or fish. I used the forumula in the directions. One scoop per 10 gallons. Within 48 hours all green slime was completely gone. I am wondering if that was maybe too much because my skimmer is still over flowing a week later after two 20% water changes and running Rox Carbon. (It could have been that I cleaned my skimmer days prior though. So if I had not cleaned my skimmer maybe it would not have foamed so long. ) I kept my skimmer running most of the time during the 48 hours to keep oxygen high. I had the skimmer cup off so it wasn't skimming just making foam that goes back in the water. I may try using one scoop every couple of months as a maintenance routine just to see how that goes. Also I have recently been transitioning to biopellets. The biopellets were feeding the cyano. I have moved my biopellet outlet closer to skimmer inlet so I hope that will help in the future. My nitrate started to creep up a little during this process ( from 1ppm to about 2-3ppm) as I had dialed down the biopellet eflluent during this process to a small drip. That was recommended to me by a biopellet reactor maker. I'm not sure if that was really necessary but he said it has worked for him in the past. If you see any sludge type stuff maybe give this product a try. Also I saw it on ebay for about half the LFS price.