No I was not kidding about the mollies......based on the info in the original post and my perception of the problem/question.
There was no mention of live rock, or other background information given, as in Random Aquarist's second post. To me, it sounded like the last tank that he cycled took less time than this tank is taking, and was asking for suggestions (including the use of bacterial additives) for helping the process along. This is why I posted what I would suggest for cycling a tank.
If I had known that there was a bunch of 'dead' live rock in the water, and that the tank was let to go bad and kill all the stuff in/on the rock.....I would have recommended differently......i.e.:
Basically, you need to 'start over from the beginning', replace the water in your tank, and act as if you just received your rock shipment. You have to re-cure you live rock. I would suggest removing it and cooking it in a separate container (links:
1,
2,
3). Then, I would get a few pieces of cured rock from the LFS, and put that in your display (with clean water). The sandbed may be fouled depending on how much stuff was in it prior to stagnation. If there wasn't much in there, then there won't be much fouling. If you are doing a DSB, it should be fine because you want anaerobic conditions in there.
You need to keep track of the water quality in the display, remember you have started over....If you elect to keep the rock in the tank, you need to do religious water changes, loads of skimming and exhibit tons of patience.
Sorry about the confusion. And you should be cycling with some live critters, too IMO. If you get some cured live rock, and slowly ramp up the bio-load (not just dump a bunch of crap in there), the ammonia levels will not spike really high.
The ammonia spike most people see does allow copious amounts of bacteria to grow, but if those ammonia levels aren't sustained the bacteria will begin to die off due to competition, resource limitation, etc. At that moment in time, there will be no ammonia showing up in the aquarium, but once the bacterial population crashes the ammonia will spike again. This results in a Lotka-Volterra population dynamic, the classic predator-prey model (fig. 1). The only way to control this swing is by waiting - over time the two populations will level out. Barring any fluctuation in the resources (like adding or removing a bunch of fish at a time), they will remain in equilibrium.
I suggest a different approach to cycling a tank. My way is done by adding a bit of bacteria, and a bit of resources (something like a few mollies to produce ammonia) and then slowly adding to the bio-load over time. This results in a sigmoidal function (fig. 2) for bacterial growth, and doesn't have the fluctuations of the predator-prey model. Basically, the bacterial population follows the ammonia level to the equilibrium without the swings. Again, barring any fluctuation in the resources, they will remain in equilibrium.
Figure 1: Classic predator-prey model (bacteria=predator, prey=ammonia)
Figure 2: classic sigmoidal curve
Sorry about the confusion earlier, and I guess sorry about the tangent of population dynamics. If you have any questions, just let me know.
