Amquel does not remove nitrates from the water. Amquel + (which is made for saltwater as well) does. It does not actually remove it. It simply detoxifies it. If you are using it in your make-up water, I would simply suggest purchasing an RO/DI unit to avoid putting phosphates among other things in your tank. If you are using it to remove nitrate build up of an existing tank, it will not remove them. The only sure way to remove them is by doing water changes.