I don't know if this was a coincidence for me, but I had cyano and algae problems before I tied in my 10G to my 50G system as a fuge adding around 60gph into and out of the tank via an overflow. What I did was add a magdrive mini 65 and dropped in 2 blue legs, 2 zebra legs, 2 red legs, 4 astreas, and a turbo. Algae and cyano went away very quickly within a matter of days.
Algae: The algae seemed to be trimmed down to nothing very easily. From having planted FW and dealing with plants vs algae, I was rather amazed at how quickly just a few hermits seemed to do against this form of algae. This was the hairy algae that looks like little tufts/clumps of hair, not the long stringy algae. I feel that even though hermits will crawl around on polyps and are very opportunistic eating other things other than algae, that they are #1 in algae control followed closely by turbos. But that's just my opinion and I'm very far from an expert.
Cyano. And note, I'm not saying the hermits actually ate the cyano. By observation, what I did notice was that the hermits would walk across the cyano and either ate it or they picked stuff off of it. The red legs tended to do this the most. My theory is by them getting on it and eating or stirring it up, it was kicked up a lot easier by the PH and that resulted in it going away faster. I tried to keep salinity, lighting, and water temp stable along with about 15x turnover (~65gph ph + ~80gph hob filter) and add nothing but topoff water. I didn't measure any other parameters. The only variables I did change were the animals in the tank. 3 months later no problems at all with algae or cyano. Now all I notice is big pods and my snails grazing on the spot/film algae that grows on the glass.
I don't know if it will return, but I've kinda got a feeling that with hermits, snails, a large pod population, added flow, a hardworking skimmer, and chaeto (that I added later), I am not foreseeing any more trouble with pesky algae and/or cyano. But who knows, it could happen. Just letting you know what worked for me. One thing about your setup that I've noticed--and I've been watching from almost the very first page--is that you have no hermits and you have algae problems, and I'm not sure if it's just coincidence. Good luck! I'll be watching/reading.
