this may help, i only skimmed but here.
"E) How to rid your freshwater aquarium of cyanobacteria:
I KNOW VERY LITTLE ABOUT SALTWATER AQUARIUMS, SO THE PROCESS YOU USE MIGHT BE A LITTLE DIFFERENT.
Start with water changes, they are the best way to rid your tank of cyanobacteria. Don't clean filters, they contain the good bacteria as well as the bad. If you do weekly water changes, you will lower the nitrate levels in your tank, which is good for your tank anyway. Also, make sure you clean the tank thoroughly including, decorations, fake plants and gravel. If you have real plants, try to clean them with a gravel vac or maybe even use a turkey baster, (try and suck the cyanobacteria off of them.) Do this every time you do water changes. The most common thoughts on this is to do a fifty percent water change then do a twenty five percent water change, then to do ten to twenty percent water change. Until your nitrate levels are at or near zero. You may need to do more than weekly water changes to get your tanks nitrate levels to zero. If the bacteria infestation still persists. Feed the fish less, they won't starve if you limit the feeding, just watch them carefully and make sure they are still healthy. Cyanobacteria does not seem to effect fish in the early stages, you might not even notice any problems at all. Continue to do your water changes. Also limit the light your tank gets. Cyanobacteria need light to survive, so by limiting the light your tank gets, you cut down the energy the cyanobacteria need to survive. Still do the water changes and keep the nitrates at or near zero. You might even put light on a timer to regulate the light more effectively. You can use the black out method to get rid of cyanobacteria, but this method is not the safest way to get rid of cyanobacteria. As the cyanobacteria dies, it lands on substrate and is absorbed by the water column. If not filtered and cleaned properly, it will cause your tank to foul even more when you quit the blackout. If you haven't filtered and cleaned enough, the cyanobacteria will return with a vengeance. Next, make sure your phosphate levels are within normal (which they should be if you are doing your water changes). Co2 and oxygen play a part in the life cycle of cyanobacteria. Make sure that you have good co2 levels and that there is plenty of oxygen in your tank. Add air stones if you don't have them and make sure you have good filtration. So what else can you do to rid tank? If you do water changes, limit light, don't over feed, make sure phosphates levels are good, the co2 and oxygen are good, and still the cyanobacteria thrives. You can use fish medication like Maredl Maracyn or your favorite type as long as it contains Erythromycin. Use as directed, don't overdose!! Medication also has draw backs. The bacteria can develop a resistance to the medication, so be careful when using. Also, medication may kill good bacteria. So you have to watch your tank very carefully. Test frequently to assure that your tank is healthy.
I found this information to late for my plants. I removed them from my tank and replaced them with fake plants. Cleaned all decorations and changed fifty percent of the water, then added the Erythromycin for five days doing water changes every other day. After two days the cyanobacteria started to fade away. After five days all signs were gone. I tested the water conditions at five days and found that the nitrates were high. I assume that the bacteria was masking the real nitrate levels to look lower than they actually were, did water changes till the nitrate levels were at normal levels. I also started to feed less food, and cut back the lighting two hours a day. It's been two weeks now and the tank looks great. The fish are healthy and active, and I feel much better that I may have found the cause for the problem. Time will tell."
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Cyanobacteria
