I've always found that any time I make changes to my tanks, I get a small cyano bloom. Normally it clears up on its' own in a few days to a couple of weeks.

It is possible that your reverse lighting could be causing it, I get the same thing occasionally in my tanks. I forgot to turn off my sump work lighting under one of my tanks a while back, and it triggered an outbreak. But, it cleared back up with no action on my part. Cyano normally only shows up if there is something for it to feed on, what are your water params?