Hairy Algae????

[busymum]

We just started our first reef tank, that we bought used its a 92g bowfront. We cleaned it with baking soda and water, rinsed and vaccumed it out. Used neutralized tap water with reef salt, rinsed the live sand that came with the tank in fresh saltwater. We also got with the tank about 100lbs of live rock that sat fully submersed in the previous owners tank water for about a week and a half in total darkness in 5gal buckets. We didn't rinse the live rock that had sat in buckets. We just placed in our tank when the salinity had reached 1.024. The water that held the rocks seemed cool in temp, and we noticed when putting the rocks in the tank that one of the rocks had a golf ball sized clump of green mossy grass that we thought was a bonus (yeah right!!!)

Because we are newbies we kept the rocks and sand and have now placed them all in the tank with our newly salted water about 4 days now. After doing some research we realized our mistake and tried to rip out as much of that little furball as we could.
It was suggested to us that we totally black out the tank (which we have done with black 6ml poly) and shut out all lights. We have a canister filter, 2 power heads and a protien skimmer running for now. It was suggested that we keep it like this anywhere from 2 weeks to 2 months. Are we on the right track or should we just start over again? How will know this has worked? Any help will be greatfully appreciated.