What I think RTR means is just leave everything intact, just like it came from the store and chuck it in. The presence of the plant won't cause the algal bloom, there needs to be light as well. Just leave the lights off. After a week or two you can remove the plant and pot and chuck 'em.
I guess I'm a little late to this
, since you've now restarted, but charting KH and pH through the addition would be helpful. What is your tap KH? pH after tap water has sat in a shallow dish overnight?
Ammonium carbonate shouldn't cause any problems, but if your tapwater was already high in carbonates, the compound may not dissociate. I should still show up in tests, but whether the bacteria can take up ammonia associated with a carbonate, I don't know. I doubt that they should have that problem, otherwise people with particularly hard water would have a really difficult time cycling their tanks, it seems to be the other way around.
I suspect that the source of your long cycle is just the lack of a seed colony. If you don't add a source of bacteria, then you've got to wait for some to find your tank by chance and establish themselves.
The water change shouldn't have posed a problem. Just enough chlorine is added to the water to kill bacteria. The fact that fish can survive, doesn't mean that bacteria can. After all, we drink it, and we're fine. Call up your water company and find out whether they add chlorine or chloramine (or both). Check what your dechlorinator treats. If it's just chlorine and your water company is dosing chloramine, there's a problem right there.
I guess I'm a little late to this

Ammonium carbonate shouldn't cause any problems, but if your tapwater was already high in carbonates, the compound may not dissociate. I should still show up in tests, but whether the bacteria can take up ammonia associated with a carbonate, I don't know. I doubt that they should have that problem, otherwise people with particularly hard water would have a really difficult time cycling their tanks, it seems to be the other way around.
I suspect that the source of your long cycle is just the lack of a seed colony. If you don't add a source of bacteria, then you've got to wait for some to find your tank by chance and establish themselves.
The water change shouldn't have posed a problem. Just enough chlorine is added to the water to kill bacteria. The fact that fish can survive, doesn't mean that bacteria can. After all, we drink it, and we're fine. Call up your water company and find out whether they add chlorine or chloramine (or both). Check what your dechlorinator treats. If it's just chlorine and your water company is dosing chloramine, there's a problem right there.