Yeah, I know what you mean. I dropped the bottle once while adding ammonia and added probably 40 ppm. Lets just say I've been a little more careful since then. That took a LOT of water changes to resolve, but since I've been doing the fishless cycle thing, I've had little to no die off in new tanks. At the fish store I worked at, I sometimes had a hard time helping customers setting up new tanks because of the astounding number of problems some of them have had from simply throwing fish into a tank of brand new tap water.