Try a peroxide dip. Mix about 2 cups of saltwater with 3/4 cup or so of regular peroxide. Dip and soak for a few minutes. Rinse in saltwater and then put back in the tank. The algae will start turning brown and eventually die off in a few days.
180g- Mostly BIG fish and some coral. ~80g Nuvo- My coral tank with "happy fish"~ 90g- FOWLR Not the not happy type of fish~ 125g- Freshwater Malawi Cichlids ~10g- Nuvo- The refugees from the Ich of '18