Jeni, it should go away with what you're doing. I have used Boyds chemi-clean before, reef safe but a band aid type solution.
This was also something I found out about but haven't ever tried it....
"Others have found cyanobacteria surviving, and sometimes blooming,
in tanks that have excellent water quality. They used a schedule of
Freshwater Maracyn to eradicate the infestation:
One 200 mg tablet per 50 gallons total water capacity (don't forget
the sump and skimmers) dosed daily for 5 days. Their experience is
that this will permanently cure the problem, without any return. Of
course, if the bacteria is re-introduced to the tank, all bets are off.
They also disable the skimmer during the treatment, and siphon off all
dead and dying material after day 3."
I'm only suggesting this as a last resort. All other methods to eliminate cyano should be exhausted first. Freshwater Maracyn is an anti-biotic, (erythromycin) and it's very possible, if the directions aren't followed correctly, to develop an anti-biotic resistant strain of cyano, so, use at your own risk. You must treat the tank for the full 5 days, 7 is even better.
The Freshwater Maracyn will not kill the biological bacteria in a marine tank. Also, I did not have anemones at the time, but I would be concerned as to what effect the Maracyn may have on them. Fish, corals, crabs and snails seemed unaffected.
Disabling the skimmer and siphoning off dead algae is a very important part of the treatment. The skimmer will go nuts because it's removing the medication. A couple water changes after the final treatment should also be done before the skimmer is turned back on.
Bob