I've been battling green hair algae for several months. My tank is 5 months
old & I started growing algae in month 3.

The problem is diminishing. So far, I've:

-Limited light from 10 hours to 6.
-Removed phosphate (using Phosguard).
-added snails and hermit crabs.
-added more water circulation (recently).

I have live rock (about 45lbs in a 75 gal tank). Nitrates are not a problem.
I'm using a wet/dry filter, and the mechanical filter part continues to fill
with algae; enough that I have to clean it every other day. The hermit crabs
seem more interested in eating the snails than the algae. I also added a
Mexican Fighting Conch, but so far, he just buries himself in the crushed
coral. I'm not using sand, but now wish I had. The tank has 4 small fish
(percula, purple dottyback, 7 line wrasse, yellow gobie) and a peppermint
shrimp. I also run a Diatom filter and do 10 gallon water changes 1-2 times
per month. Temp is a pretty constant 80.

I'm resisting pouring a chemical into the water to make it go away, but the
tank looked so good when I first set it up; I'd really like to rid the tank
of the algae. I keep reading this group and everyone says "patience." I'll
try to keep listening....

-Tom