By the way, nitrates of 50 aren't all that bad, but 20 is alot better. I would not stress about them now. Once the tank is cycled, if they are still consistently higher than 40 or so, then we can look at what might be causing it. I would also only feed every other day or so (or even less often), the fish will be fine and it will help you keep the numbers down. Rinsing the filter in tank water once a week or so will also help 
