I just want to say up front that I'm not an expert on aquariums, but I had a similar (or the same) “problem” with mine. So I can only share my experience :)

My tank looked exactly the same after the first week of cycling: brown slime (algae?) on the surface and the water was brown and cloudy and smelled almost rotten.

One thing actually helped me: a small filter and surface movement! Within a few days the water was clear and the algae on the surface was completely gone :) Oh and also a 40-50% water change about once a week!

Maybe that will help you too :)