Prime does not remove any ammonia. Instead it will cause the ammonia in a tank to be less toxic to fish. I use only Prime in my tanks because it contains the same active ingredient as in most dechlorinators and does the job with very small doses. That makes it economical to use, which definitely matters when you run 26 tanks like I do. I get about 1 ppm of ammonia when I measure my tap water after dechlorinating it. What I find happens is that the ammonia is gone just a few hours after a water change. The biofilter in my tank has simply converted the ammonia right through from ammonia to nitrite to nitrate. I almost never can find any ammonia or nitrite in my tank unless I test it right after a water change, before my filter has had a chance to work on that ammonia in the tap water.