**sarahp**
Fishaholic
You won't see but one change in nitrite. One morning it will be off the chart and that evening when you test again, it will be zero. It literally does drop that quickly. Once again it makes sense that it would happen that way. If you figure that the bacteria are doubling every 24 hours or so, and say by the time it is almost there, there is 30ppm of nitrite left. If at that time there is enough bacteria to process 15ppm in 12 hours, then one more doubling would handle the full 30 so it would fall to 0.
Oh yeah *doh* makes perfect sense when someone points it out to you - its like a dark art this fish stuff
I knew I should have paid more attention in chemistry when i was at school 
Didnt even know it was an option, or is it supposed to be set as standard unless you alter it? Cant rmember it being asked when I joined either