Cyano and Spurulina, wait, what!

[Coronus]

So I have learned something new since being on r2r recently. That I might have spirulina? Which I thought was blue green cyano. Its on my sand bed. It makes the sand hard in patches. I have had it a while now and I usually syphon some out during water changes.
How can I defeat it? I have never even heard of it except for it being in my frozen mysis?
I have no other algae in my tank. Params
Cal 425
Alk 8.4
Mag 1400
Potas 400
No3 0
Po4 0
S.G. 1025
Tanks 5 years old sps system.

 

[CastAway]

@twilliard might be able to help. ;)

 

[twilliard]

https://www.reef2reef.com/threads/positive-identification-of-cyanobacteria.253287/
is the first step