Hi and welcome. I am curious about the "stuff" that is supposed to cycle your tank. I am assuming that it is some sort of nitrifying bacteria. If that is the case, I was under the impression that you should add fish sooner than a week in order to feed the bacteria. I may be wrong, and I am sure someone will give a correction if that is the case, but the bacteria need the ammonia from the fish waste to survive. If they die, before you add fish, then you will need to add fish very slowly. Like maybe 2 at a time and test water for several days after first addition. If the water is safe, then you can add more gradually, testing as you go. As I said, I may be wrong and the bacteria can survive for a week without ammonia, so please everyone chime in on this.