Most likely the gravel had both the bacteria necissary to break down ammonia, as well as the ones that break down nitrites.nshockeyplaya said:Hey i just checked my ammonia and nitrite today, and i got .5 on my nitrite (why would it be going down, shouldnt it be goin up?), and i got 5.0 for ammonia. This doesnt make sense. ANyone know why the nitrite is goin down?