Hermits won't help with the Cyano, and contrary to what a lot of people say, I've read and been told that Cyano is almost unavoidable at times, in newly established tanks it's not uncommon to go through the different phases of algae blooms. Cyano is technically a bacteria but it looks like algae!
People will suggest your light bulbs are old, your water is bad, not enough flow..etc. I have 4 bulbs that are 5 weeks old, a #2 & #3 Coralia with a Fluval Canister in a 36g CORNER tank, I have a ton of flow and I still had an outbreak of Cyano. My LFS told me continue with my regular water changes, make sure I'm not overfeeding and it will sort itself out with each water change. I reduced the hours my lights are on too, it really seems to have helped....
You treated Ich with medication, I would not do this in your display tank. It appears that chemicals are a last resort, but if you have a small 'hospital' tank and patience, you should never have to treat your display tank and risk the lives of your inverts, coral & overall stability of your tank.
Cyano info here
http://www.reefs.org/library/article/c_bingman2.html
and Dan is correct.. some things eat it but its not our typical clean up crews...and its in everyones tank... when it becomes visible and slime like is when you have too much nutrients in the tank which allows it to grow like mad.
Flow...only prevents detritus from settling and prevents dead spots where cyano can take hold and grow... its one preventative measure but its no cure as Dan stated. Ive had some grow on a powerhead...
Every tank is different on the root problem ..the only thing similar is Nutrients in abundance. Where is the question... the water? the substrate? Both?
For me I had one hell of a nightmare almost 2 years ago...and it was my substrate was so saturated with nutrients...i would siphon out the cyano...next day I had a 3"-6" lengh and width blanket on my sand of red slime...
Cyano clean up is a pain because it has to be hit two ways...
1st is total clean up..siphon all you can.. blowing off rocks...siphoning top layers of substrate .. huge water change.
2nd is prevention and that means identifying the nutrients source..your water, your maintenance not good enough, over freeding, ..what ever it is you have to nail it down by observation on your end.
The slow way but sure way is just lots of water changes and often siphoning what appears till it finally cuts back. That can be costly for some tanks that are large.
ugh I can tell yah I do everything I can now to prevent it from ever happening... I strictly avoid Canisters, Hob filters...another reefer and I both had similar stories of nitrates being high..and removing canisters and they finally dropped and stayed down with regular maintenances.
I also run phosban in a reactor to ensure phosphate is never present... no joke its like tossing jet fuel on a fire ...when it comes to cyano and algae growth.
