I had pretty bad cyano. Had to remove chemical filtration while treating ich and cyano got crazy. After I got the ich knocked down with herbals and UV sterilization, I took the vacuum tube off of my siphon, and vacuumed with just the hose to remove as much cyano as I could (very effective with just the hose). Then I dosed chemiclean (follow the instructions). After 24 hours I had 95% eradication. Instead of water changing and redosing, I left it in for 12 more hours (not following the instructions) and had zero trace of cyano then I did the prescribed 20% water change and added back my chemical filtration (purefiltrum, or chemi-pure, or carbon, whatever you are running). Been looking good for a month now. If you use chemi-clean, and you do not "wipe out" the cyano, it can build a resistance and become SUPER CYANO.