The only time I've ever had trouble with cyano was when I was carbon dosing a few years ago. Didn't seem to happen with vinegar but when I switched to NOPox it started. I've heard lots of people relate that ethanol dosing was what did it to them as well. Hope you get it knocked out! It is amazing to find out that what we used to think was mandatory (undetectable nitrate and very low phosphate) is actually dangerous to the health of our tanks. I'm seeing some improvement in my dinos but I think it will be a long battle. (nitrate is now 2.5, phosphate is 0.04)
