I agree with Bobby, keep your lights on for 8 hours a day. I also have never gotten a starfish in any of my live rock (and I have about 125 lbs).
The starfish are more sensitive to water parameters than fish. So adding a star will be more risky than adding a fish. They will disintigrate if nitrates are too high.
My lawnmower blenny does not eat green hair algae. He only eats the brown algae, so one may not do any good for the kind of algae you have. Like someone else said, going through a series of algae outbreaks is normal in the beginning.
I am battling green hair algae myself right now. The only way to get it under control is to lower your phosphates to 0 and get your nitrates as low as possible. Algae need a few things to grow: light, nitrates and phosphates. You need to take multiple actions, by depriving it of light, and starving it of nitrates and phosphates it will die off on its own.
The only animal I have found that eats the green hair algae is a sea hare. They are very sensitive to water parameters and some will release a purple toxin when stressed, so I wouldn't recommend one for a new tank :( But mine does an excellent job of cleaning off whats left of my algae from the rocks.
Algae takes A LONG TIME to get rid of! My outbreak happened about 5 months ago and it is still not under control, but it is getting better. You may not be able to see your tank, but at least algae isn't hurting anything. Don't stress too bad over it, you'll slowly get it under control.