75 gal Tank

[polyp02]

So here is an update on my 75 gal. tank. As you can see no corals yet only fish. I have a clown(false), 2 damsels, 1 chromis; shrimps 2 camels, 2 peppermints & 1 cleaner; 1 sallylight foot, and 6 hermits; 2 turbos, 2 nassarus. I actually have 2 corals the green polyp stony and just bought a frag of mixed buttons. I also bought some more live rock. I bought one that had some green grass growing on it which might have been a bad idea, since then I've been getting green hair like grass growing all over the tank, in the rock and on the surface(see pics). Also I can't make my green polyp grow, it still looks the same size as when I bought it only the fish are growing. I'm thinking of just spending $40 and just buy a mature coral.
That is all the update I have so far.

 

[klepto]

The "grass" that you are talking about is some sort of nuisance algae. Seeding your tank with such algae is not a good idea. It will discourage coral growth and you will be battling it for months to come.
If your water is 'clean' enough (low nutrients) then the algae will eventually die off. Keeping up on water changes (with RODI water) and feeding a reasonable amount of food (rinsed if it is some oily frozen food) will minimize waste and thus food for the algae.
It's up to you, but I would definitely pull the rock that is loaded with the algae. Some herbivorous fishes can help, but minimizing the algae manually is important.