White filament on aquarium walls and decor

Question
Dear Matt,

I have a relatively new 75gal aquarium
housing an albino lemon oscar, a tiger oscar,
a jack dempsey, green terror, and a jewel
cichlid. All fish are less than 4in. So its not
overcrowded yet. Well, my question about a
tiny clear/whitish filament of some sort that is
growing on the walls of the aquarium and the  
large rock I have. It doesn seem to be
bothering the fish as they are doing fine and
growing at a fast rate. However, the filament
is starting to get on my nerves because I'll
clean it off then do at 25% water change and
it's back within a week.  

Answer
Hi Ryan,
I believe this occurs in a lot of new aquariums.  If the tank is high in nutrients with readings of ammonia, this filament usually occurs.  What are you using for your substrate.  Nutrient rich substrate leaks nutrients into the water causing the growth of this filament.  It goes away on its own.  It will always keep coming back until the water column is depleted of the nutrients and organic material.
-Matt-