I think the bacteria does need a bit more than amonia in the tank to really do the trick though. The amonia will get the bacteria started. But the fish waste is what will sustain them.
"Sustain" was the key word in my post. Yes, you can have a fishless cycle. But what happens to the cycle as the amonia disappears? It can complete, or it can slow down dramatically if the bacteria hasn't gotten a good hold yet.
It is the by-product of having fish in the tank that will SUSTAIN the bacteria. That was the point I was trying to get across.
asincero, a couple of things. I can't find any mention of your nitrite level. Is NO2 present? Are nitrates rising? They should be if you have bacteria that will consume NO2 -> NO3. What is the NO3 level in your tapwater?
Also, what is your KH and pH? It's important to have a good buffer in your tank when your doing the cycle.
Actually, the ammonia is like bacteria "food". You're right, if you don't keep adding ammonia, there will be no food source and the bacteria will die. Adding fish gives the bacteria a constant supply of ammonia (fish waste). This can be replicated by dosing a certain amount of ammonia daily. People use this method to keep an empty hospital tank cycled...SUSTAINING the bacteria until fish need to be quarrentined.
asincero, we want to know you KH and pH because as the bacteria converts ammonia to nitrite to nitrate, it uses up the KH which is the buffer that keeps your pH stable. Once too much KH is used up, then the pH can crash and kill all your bacteria. This may have already happened, which would mean you need to start the cycle over. Doing partial water changes maintains that KH buffer, stabalizing your pH.
It is also common for the Nitrite portion of the cycly to need a second dose.
Given that you had an initial drop in ammonia, and then it stalled, I'm guessing Kh depletion as well. Since there are no fish in the tank, Test the numbers if you can for a baseline and then add 1 teaspoon of baking soda per 30gallons. Re test and repeat until you KH is above 3 dKH (53-54 ppm).
The ammonia portion usually only stalls or slows if starved of ammonia, or if KH is depleted.
As far as Bio-Spira, as mentioned. if handled properly it is the correct bacteria, and is live bacteria. The beauty of fishless cycling is that if you get a bad batch you haven't created an emergency for yourself.
There is no difference between ammonia and Ammonia. It does not have to be from fish waste, it can be from a bottle and is still the same ammonia. The bacteria will not know the difference. If there were enough live bacteria in the original bio-spira packet to drop the ammonia level, something else is amiss with the set-up. Once again I'd look at KH.
Check the cycling article linked by TDWagner, it has a lot of info and hints that may help you.
