Whats next? 3 weeks old tank ...

[Reefcan]

My 95 gal tank is been setup about 20 days, 100 lb cured liverock with some sand. never been changed water. Now the green hairy algae is growing crazy. there a sea hare/couple white urchins/2 shrimps/2 yellow gobies with 10 snails in the tank, hope can get rid of the algae. Am I doing it right?
Now the algea getting less very slowly, some of them grown very long,I have to pick them off by hand. I'm afraid of to buy any fish right now untill the tank is nice and clean. I tested water once a week, everything shows OK.
I bought couple rubblemaid containers with a water pump, try to change the water tomorrow. Should I ? what u think?
Is a refuge will help for the algae?
Should I just wait untill the algae is gone by itself ? When is safe to add fish? Kids want the clown fish so badly!!!
Thanks for any comment!