According to Jungle Labs (the maker of "Start Right Aquarium Water Conditioner for Salt or Freshwater"), the product "Removes Chlorine, Chloramine, and Neutralizes Heavy Metals." If your local water contains chloramine (a combo of chlorine and ammonia), then using this product will ADD ammonia to your tank water. A better product if your local water company does use chloramine (just my opinion) would be to get Seachem's Prime. It removes chlorine, breaks the chlorine from chloramine and then binds the ammonia, and neutralizes the heavy metals of the water. The only trouble is that the ammonia level will still show on the test kits used by those in the aquarium industry, even though it is in a form that is not harmful to fish. I recommend getting an Ammonia Alert disk sold also by Seachem. It reads your ammonia level 24/7 for a year (I've had one going since February of last year, so they can last longer). It will ignore the bound ammonia that shows up on the standard aquarium test kits, so you can know the water is safe.