I had an overwhelming amount of red algae, I mean obscene amounts in my biocube. I did one dose and it was gone the next day. i did a water change to be on the safe side and haven't had one single re occurence show up. Nad I mean I had alot, it was hanging off rocks and peeling off the back wall. I also know why though. I overfeed like a crazy woman due to weaning my scooter and mandarin onto prepared foods and my flow was a little lacking.
It's always good to fix an issue causing the algae rather than just dosing the tank. But I had great success with using it.