This ammonia deal has to do with chloramines, too. I'm pretty sure if any conditioner removes chlorine and chloramines, it will take care of ammonia, too. I think there are laws about chloramines being used in larger metropolitan areas, but smaller towns (like the one I live in now) still just use chlorine. The chloramines hold the chlorine in the water for a longer time. In Austin, we always double dosed our conditioners because if you didn't, and did a big H2O change, you would get an ammonia spike. Saw it happen all the time in customers' aquaria...