I got that in the last tank I cycled, I always assumed it was diatom algae. Regardless of what it is, you can just brush it off, it should clear up once your tank is more established.
It looks like you also have planaria? Tiny little white worms rippling through the water? I got those at the same time as the brown algae, it also cleared up on it's own when my tank was better established.
BTW, you should look into upgrading your lighting if you're using Eco-Complete and ferts. Otherwise you'll end up with some major algae problems later on. Plants need plenty of nutrients, light and co2. Have too few/too many of any of them and the algae takes off.
Last thing, I think the plant you have is a crypt. I could probably tell you more definitely if I could see the base of the plant as well, but that's my best bet.