If the issue is ammonia in your source water, being tap water, you need to use a water conditioner that detoxifies ammonia along with the basic of chlorine and chloramine. Not all do handle ammonia, but it will say on the label. Most of these work by changing toxic ammonia into non-toxic ammonium. This is safe for fish, and the "change" does not reverse.
The nitrifying bacteria and any live plants will take up the ammonium same as ammonia. There is no need for special ammonia removers.
If the ammonia is occurring within the aquarium, not in the source water, that is a very different thing. But I assume from what has been posted so far that it is source water ammonia. The tap water should also be tested (alone) for nitrite and nitrate, as either of these can be present depending upon the source of the water. Nitrate for example is common in agricultural areas.
Byron.