Elaine T wrote:
It usually works because there are almost always active nitrifying
bacteria on the leaves of the plants which seed the tank. This is
because there are fish, snails, shrimp, or other forms of
ammonia-producing aquatic life in the plant tanks of most fish stores.
Start with enough plants and you get enough bacteria to avoid a "cycle".
The plants also directly absorb ammonia, but I honestly don't believe
that's why you can get a cycle-free tank with enough plants.


I don't usually sterilise plants, some do though with potassium
permanganate, hydrogen peroxide and bleach. I bet this has an impact on
that beneficial bacteria.

Nikki