Hair algae is something that scares a lot of people and for good reason.
I only have one place in my reef where I grow it on purpose.
This was a string that I had tied to a coral that was at one time suspended from above the tank. I cut the string and let it unravel. It grew this tuft of hair algae in no time. I also collect amphipods like this, I cut a rope and unravel it. Then I hang it under my boat. It gets loaded with amphipods in a few days. This would alo house pods in a tank if I allowed it to rest on the substrait and is a good way to have a safe haven for them.
I find this one piece of hair algae interesting so I leave it alone. I don't have any tangs at the moment and the algae bleeny is not interested so there it stays.
Just felt like sharing

Wow! Really very nice, its good to see this post.