i have used nite-out before.. added it to a quarantine. i also used it in my main tank because the woman at the lfs recomended it. she is pretty good about fish care ect. my reason was to bring down nitrates. it did lower nitrates by 5ppm. i didnt have a prob with amonia/nitrite but i am guessing it did react the way it should have. that is my only exp. with that kind of additive.