Hi all,
The point is, I know exactly what it takes and how long it takes to cycle a tank fishlessly with ammonia, and that it will take the full bioload at once..
This is really down to probability. I know that you can "cycle" your tanks using added ammonia without any problem at all, in fact people who keep tanks without plants, or substrate, are obliged to use this method, because they are entirely reliant on the nitrifying micro-organisms in their filter.
My point would be that keeping tanks without plants and substrate is an inherently unsafe method of keeping fish, because you have a single point of failure, the filter. You can mitigate for this, to some degree, by having a wet and dry trickle filter, but even then, as soon as the tank water stops entering the filter you have a positive feedback loop of declining oxygen levels and rising ammonia levels, and fish death becomes inevitable.
If its an inert substrate tank, you've got to wait a long, long time for a sufficient cycle to go through due to lack of ammonia....unless your plants start rapidly melting giving off something for the bacteria to work on...
This isn't strictly right. The problem is that it starts from the premise of a linear progression:
ammonia > nitrifying bacteria > cycle.
But we know that isn't true in the planted tank, it isn't a linear process, but a much more complex web of interactions including: plants, bacteria, archaea, oxygen and ammonia.
Plants take a few weeks to establish and start actively growing, before that they do nothing but pollute the tank...
If you have a floating, or emergent, plants they aren't CO2 or oxygen limited, and they can very efficiently convert ammonia into plant tissue from the moment they are added to the tank. The capability of plants to assimilate fixed nitrogen is hugely under-estimated by most aquarists.
Plants are net oxygen producers, they take up NH4+, NO2- and NO3- and they produce a complex rhizosphere within the substrate. It is the plants and oxygen, and the micro-organism assemblages that they help foster, that are really important, not the level of ammonia.
As soon as your tank is planted it is an "ecosystem" and for ecosystems complexity builds resilience.
cheers Darrel