It does not look like turf algae, it looks like Calothrix sp, a filamentous cyanobacteria. There have been some experiments with Fluconazole in the treatment of Calothrix, which have been successful, others have not.
I would try, before Fluconazole, a treatment with Azithromycin at the dose of 3 mg / gallon in a single dose. The skimmer must be kept on for oxygenation and pH stability and the skimmer cup must be removed so that the skimmer does not remove the medicine. Activated charcoal and / or Purigen must also be removed. The drug's action is rapid. In this dosage, in 4 to 5 days it eliminates the cyanobacteria. Once this has been done, the skimmer cup and the activated carbon are returned and within 24 hours Azithromycin will be eliminated from the system and a partial water exchange can be made if the parameters are changed.
Whenever antibiotics such as Azithromycin are used, the nitrogen cycle in the aquarium should be monitored for the possibility of the antibiotic unbalancing the biological filter and producing a peak of ammonia. In my personal experience with Azithromycin this rarely occurs if the correct dose is used. In several times I used this medicine only noticed a slight increase of nitrite, ammonia did not appear and the nitrate remained stable.
In my experiments no adverse effects on corals or any other animal in the aquarium were noted.
Best regards