This reply is if
you have only have Cyano. If Dino's then my comments don't apply. (Big DIFFERENCE between Cyano and Dinos...KNow what you have before applying solution)
FYI.
My nitrates have been 50 in one Tank, and 100 in another. No Cyano. Corals fine.
So don't worry about nitrates (Like I used to).
I just Recently I decided to tackle Phosphates with GFO to keep around 0.1 since naturally my SPS Tank runs at 0.4ppm (Not sure if I actually needed to do that, but Hoping SPS grow faster)
Before I decided on GFO, I was thinking NoPox.
Since I hate Cyano, and noticed that it increases risk of Cyano, I decided to not use it.
I've had bad Cyano many times in the Past, and I learned that Over Feeding Tank (Corals not Fish) was the Cause.
I used to do Amino's daily in my SPS tank. Sure the corals colored up, but so did the Cynao outbreaks.
Now I dose Amino and Feed Corals once a Week.
Corals not as colored up but better, but greatest thing is No Cyano. It actually went away on it's own.
If you
stop what is Fueling Cyano. Turn down, or off Lighting (short term), Siphon the Cyano out of your tank it will go away (without any treatments)
Be patient, since it will take about 6 weeks, and up to 2-3-4 months to really be gone.
One thing I used is Cyano Clean from ZeoVit. It's a bacterial that will outcompete Cyano. Not cheap. Speed things up, but it not a over-night miracle cure.
BTW. Looking at your photo, you don't have a major Cyano Outbreak.
This was mine. (Before and After...sweeping and feed reductions and some patience)
Of course, I never learned my lesson and got back into Feeding corals (Too much).
This was the result (WAY WORSE THAN CYANO)