My thinking on this hole thing is that reef critters really don't dig hair algae. Really nothing in the ocean does. I have been on reefs in hawaii, the bahamas, cancun, cozumel and the keys and really have never seen hair algae on a thriving reef. The algae that grows on reefs is more of a tannish color or green macroalgaes but not hair algae. So I don't believe reef critters actually like it. The only place I have ever seen hair algae in the ocean is in marinas and near hotel water discharges which probably has a lot of phosphates from the detergent in the washing machines. And as I recall nothing is eating it and it is growing out of control. I have seen some places on video where hair algae has started grow on a healthy reef and wiped the whole thing out because nothing eats it. All I know is that in 5 years of reef keeping I have probably spent $300 on critters to eat hair algae and nothing ever has. The poor things usually starve death or get caught in powerheads or something.