do nothing.
it is prolly diatom algae. very common in the first 2 months of setting up a tank. i just let it take its course. eventually the sponges in the LR will bind up the free silicates in the water column and the diatoms will just dissappear. any critter you add to eat it will then poo out the silicates. this is then more food for the diatom algae. untill it runs it course there really is nothing you can do.
this is why it is generally recommended to just let the tank sit running for 2 months to cycle. there is a lot more to cycling a tank than watching ammonia, nitrite, and nitrate.
G~
