@ McAttack, Yeh like I said Ive heard mixed results I think possibly some of the reputable brands (like Hagen that you used) might have nutrients and stuff that promote the fast growth of bacteria, but its the kits that claim to have live bacteria in them that can be a bit iffy imo. Im not expert on it either but I work in a lab so I know whats required to maintain a bacterial colony and its much the same as any living organism it needs food, moisture and oxgen. Bacteria multipys at such a high rate that in a bottle it would use up all the available nutrients in almost no time. So unless it was chilled or frozen (to reduce the rate of multiplication) the bacteria would die off very quickly ....but since Im not up to speed on the type of bacteria used here it could be a spieces that leaves spores when it dies which when introduced to the tank along with the nutrients in the bottle could bloom making a fast growing colony of good bacteria.
@ BeautifulBettaFish the easiest way to get ammonia without hurting fishes is to put some raw prawns in a pop sock (Panyhose for you people over the ocean

) and leave it to rot in the water of your tank, test the water each day after about 2 days to see what your ammonia lvls are, check up the link on this website for the fishless cycle for the rest of the info if you havent done it already, it really does work .....honest