Have you cycled the aquarium? The 0 nitrate reading seems to be that the aquarium has not cycled yet and the cloudy water that you are seeing may be due to a bacterial bloom.
I think Darkblade is right, this is the bacterial bloom. It may takes a couple of days, one week, even two sometimes before it slowly disappears. Then it means the cycle is started and you can begin to slowly
This is normal, but there should not be any fishes in the tank before the cycle is started normally.
Last edited by micheljq; 11-29-2012 at 08:33 PM.
Reason: add. details