i was running carbon, rowaphos, skimmer, denitrifier all at the same time as i was dosing algaefix, i have a 90 with a 30 gal sump, come to a total of 120 gal minus rock, coral, sand, equipment, etc, it came out to roughly 90 gal of water so i did a capfull or 10ml of algaefix marine every 3 days, by the 5th dose i scrubbed a little to lossen it up and it literaly dissapear by the 9th dose, all i can say is maybe try it one more time and give it time to work, or maybe the algae is not hair algae but bryopsis
sana