Smelly water

Question
I have just set up a 75gal. aquarium about 3wks. ago.  I have 4 Oscars in it.  When I open the top to feed them, an awful smell comes out.  The water is clear.  I am using a EHeim canister filter. What could be causing this problem?

Answer
Hi Gail,
 The problem is everything that you describe above.  It takes awhile (about 6 weeks) for a new tank to "cycle". During that time, the various bacteria that actually keep a tank clean and in balance are going through rapid population explosions trying to keep up with the sudden input of fish feces.  The smell is ammonia and it tells me that the bacteria are not yet keeping up.  The solution is simple.  You need to start doing some major water changes.  You should start by changing 25% of the water today, then do the same thing tommorrow and possibly even a third day. That should get things under control for the immediate time being. Then you need to start a regular program of changing 25% of the water once a week, every week.  This is the normal maintenance routine for a fish tank, particularly one with oscars.  (Oscars eat alot and make a lot of waste).

 This is IN ADDITION to having your filter working properly all the time.

-- Ron
  rcoleman@cichlidresearch.com
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