[michika]

Here are some of the potential causes that I found with my battle with hair algae.

1) Changing out all bulbs, a more yellow spectrum seems to lend it self to algae growth
2) Macro algae, and a variety of macros at that.
3) RO/DI water
4) Manual removal of the algae
5) Running the tank with a reduced photo period
6) A Blackout period, I hear it works for some, but it didn't do anything for me.
7) Run a phosphate remover
8) Larger water changes
9) Ensure all your water parameters are in order with limited fluctuations
10) Add additional members to your clean up crew, e.g. hermits, urchin, lettuce nudibranch, seahare
11) Remove rocks and scrub them all down and pluck them clean.
12) Run a Nitrate spong or remover
13) Changing your salt brand. It seems that some salt brands may have phosphates.
14) Add in GHA eating fish

I hope something works out for you!