I had cyano for a good month. Now, I can't even see a speck of it. I did a whack of reading on how I could beat it. Some of the trends I read, which many have stated here, are:
Increase water flow. Definately grab another powerhead, possibly even two. You don't have to have a hurricane in there, but you do need to have EVERY area with sufficient flow. Be sure not to aim the flow at corals that aren't appreciative of it. The ocean has high flow, often much more than an aquarium can simulate, but it isn't pinpoint targetted and constantly blasting the same direction like the results of a powerhead. Some careful angling and common sense is the key there.
Cyano, or the stuff you see isn't really the algae itself but a product of it. The cyano is actually underneath it. The stringy slimey crap is a food source it grows for itself. Yes, they are evolutionary evil bastards. I read that it is recommended for OTHER algae types, that you let it grow and grow and grow so it will eventually grow so big it will starve itself to death. But not the case with cyano as it grows its own food. So manually remove what you see, when you see it.
Test for Phosphates, Silicates and Nitrates, as they are the foundations upon which cyano develops. This is most often the source of the problem, and is where you should hone most of your efforts.
Silicates are often found in your water source (hence RODI during water changes). There are chemical means to remove silica from your water (filter bags that contain a grain-sized medium, but many sour upon unnatural ways of reefkeeping. Plus, chemicals don't only impact the cyano, they effect everything in your tank. And though the box they come in claims it is safe, many are skeptical on how the word 'safe' is defined by such manufacturers. Having said this, my readings showed a lot of people who claim positive results with no negative stories. No personal experience to share on it though.)
Nitrates develop from excess accumulated bacteria, hence removing your bio balls if you have any, and the cleaning of your filter as it builds up excess bacteria over time. Nitrates are also closely impacted by Phosphates.
Phosphates come from excess food in your tank, and I think can be found in your water source as well. Again, RODI will help here. And ensure to give your critters about 3 minutes to eat after you feed... if there is food still floating around, you're feeding too much. Scaling back the amount you put in per shot, but increasing the number of times you feed can be a good way to address this. Also, critters like Brittle stars (not the green kind as they are pred
atory) make excellent
feeders of left over food that have lodged into rock or on your sandbed.
Algae growth proteins can also come from when you put your hands in the tank. Cleaning them really good before hand, or using latex gloves can help with that.
I have also read, I think... that the light cycle promotes phospate development. Thus the comment about ensuring your lighting isn't on too long.
Increased water changes (though if the problem is in your water source, this may actually promote the cycle).
Here is a link on water parameters. I found it very helpful:
http://www.reefkeeping.com/issues/2004-05/rhf/index.php
Also, you mentioned your tank is 3 months old or so. Your anemone and scallop might have died because your tank hadn't matured enough. I hear one should wait atleast 6 months before adding invertebrates like these. I started with soft corals (daisys, xenia, toadstool) and that was after a good three months of letting the tank mature. Hope that helps.
