Help !!! on algae

[spoiledberners]

I need help getting rid of the algae in my tank. I have a 90 gal live rock and sand only. I have several inverts (10 nassarius, 20 hermits, 6 emerald crabs, 5 conches and 20 turbo snails) and one damsel. I set it up around April 2007, it started as diatoms and then turned into a green algae. I have been doing 10-15% RO water change every week. I have tested water every week as well (ph 8.2, nitrate 0, nitrite 0 and ammonia 0). The specific gravity is between 1.021-1.023. I only keep the lights on for 4 to 6 hours daily. The tank is situated in a dimly lit area of the house and no direct sunlight hitting the tank. Don't know what else to do, PLEASE HELP !! . I have attached a photo of the algae below.
Thanks,

 

[reefernana]

If you didn't have that algae, your inverts would have nothing to eat.......lol! That's a good kind. Usually a precursor to coraline. Now, if you're getting too much hair algae, you can put in a lawnmower blenny and watch him go!

 

[spoiledberners]

Thanks