I fought a battle with cyano
and won. If you take a small net and scoop up under the cyano
then gently shake the net, the clean sand should fall throught he net and leave you with a clump of cyano
that is easily dispossed of. This will not cure the problem but at least minimize it. You may have to do it often until you find the cause of the bacteria. Mine was a slight presence of Phosphates, (it soesn't take much), and the wrong lighting. I found that frozen brine has an incredible amount of Phosphates.
What seemed like a major battle then was merely a little inconvenience once I figured out the cure,(with a lot of help from my freinds here).