The cure for hair algae in my system was not any one specific thing. It was a combination of fixes. Small, weekly water changes (with RO/DI) to remove as much as I could manually, running phosban continuously, and the addition of zebra hermits.
I've experienced problems with hair algae in all three of my systems. One I started with tap, one I started with tank water from my bigger tank, and one I started from scratch with RO/DI. This combination solution has worked in all three systems.
I'm not sure I would recommend zebra hermits. These were sold to me as dwarf zebra hermits, while the majority of them haven't gotten much bigger than a nassarius snail, I've got five that have grown to be about an inch across. The bigger ones are mean and kinda creepy looking. I now wish that I'd picked up scarlet reef hermits instead.
There is no quick fix for killing hair algae. It takes a combination of things to remove it from the system and outpace its growth. I also certainly would not recommend using something like chemi-clean to kill it. I have one rule about my tanks, it has served me well for the last two years so I am going to stick with it. If I don't know what's in it, or what it is, it does not belong in my systems. Chemi-clean lists no ingredients on the package.
J.