OK.
Here's the game plan. I did this when I had my old NC12, and the algae didn't know what hit it.
1) a: So get a bag of chemi-pure (follow the intructions and rinse it a bit with ro/di water before putting it in).
b: Get 2 pads of Poly-filter
2) Mix about 10 (even more if you want) gallons of saltwater and have that ready.
3) Srubing the rocks:
Option 1: If you can, take your rock out and scrub it with a toothbrush.
Get a bucket,take out the rocks, fill it with enough tank water,
and srub the rocks like it owes you money! Then take some of the
newly made water to rinse the rocks and put back in tank.
Then re-fill tank with the rest of the newly made saltwater.
Option 2: If you can't. Since the algae seems spread all over the tank
already, you could maybe scrub the rock in-tank and have a
syphon in the other hand and syphon the crap as you scrub.
Then refill the tank with the newly made saltwater.
4) Put in your Chemi-pure pouch in the filter.
5) Run one pad of Poly-filter (see if you can fit the whole thing in your filter...if not you can cut it). See if you can wrap it around the Chemi-pure pouch. Let that pad run for 24 hours, throw it out, and replace it with the new one.
6)Then you try not to feed your fish (if you have any)...or keep it at a minimal, not stick your hand in the tank or add any crap for a week....basically zero-ing any nutrient addition.
Then come back and tell me how it went.
If you have too much rocks, you can do part 3) in stages. But would need to mix more water to rinse the rocks/ re-fill the tank.