Yeah sounds like exactly the same that happened to me. Starting coming in at about 4 weeks got really bad around the 5th or 6th week then was gone by around the 8th week. It just died off and dissapeared.
I found a really useful way to remove it was to use a toothbrush. It gets in between the strands of hairgrass and pulls the algae out while leaving the hairgrass in place (mostly
). You can also use it to "catch" strands and the twirl it round to make it easier to get it all out (think "eating Spaghetti").
I did cut my lighting down a bit but I dont think this made any difference. Regular water changes might help as well (I did two water changes a week while the tank was cycling until the hair algae went away) I have nothing to prove that it will though