The denitrifying bacteria are pretty robust and they definitely can live in a bottle for a while.
There may be plenty of dead bacteria in those commercial bottles, but as long as there are some alive, they will repopulate rapidly once get into a tank. They double their colony size in matter of hours.
There may be plenty of dead bacteria in those commercial bottles, but as long as there are some alive, they will repopulate rapidly once get into a tank. They double their colony size in matter of hours.