We started a tank on Christmas Eve with 6 tetras. 3 months later, the tank still had never reached a zero ammonia reading, although we were getting nitrite here and there. (One day it was there, next several it was not, etc.). When my 4 year old son killed the fish (he wanted to show his little cousin how to pet them...?), we left it set with a high ammonia reading (off the charts) for another 3 or 4 weeks. It never changed. We emptied it out and started over with some media from an established tank and 3 blackhead minnows from the bait store. That was the last week of April. Still have ammonia off the charts (it's nearly blue) and zero nitrite. Where is this magical ammonia eating bacteria supposed to appear from??? (We use API products for tap water treatment, testing, and feeding)