Algae problem

[Tuan’s Reef]

So I have had this algae for 3 -4 weeks now. Looks like cyano but not sure as I don’t have a microscope. I do normal 20% WC weekly or bi weekly.

I don’t have a phosphate checker so I don’t know if my nutritents is too high but my nitrate is good according to API test.

 

[Tuan’s Reef]

I can see my emerald crab and snails pick on it at times but it comes right back.