bottle bacterial won't cycle a tank unless the bacterial has an ammonia source to feed off most of the bacterial will die very quickly I have been keeping fish for over 20 years in that time have tried a couple of different brands of bottle bacterial and found no difference in how long it took to cycle a tank just a waste of money I like to just add small amount of food daily for a couple of weeks then gradually add a small group fish every couple of weeks to allow the benefial bacterial time to catch up