Originally Posted by Shiverrz
Thank you! That's exactly what I wanted to know (: Will it take the same amount of time as the initial stocking or less?
Once the bacteria is established, they reproduce very quickly as long as there is enough dissolved waste in the tank water to feed them. More food, the faster the reproduction process moves. Eventually, you have enough bacteria to use all the ammonia and nitrite for the number of fish in the tank. That's why you have daily tests that show "0" for these forms of nitrogen. The tank is cycled.
Remember, there are no bacteria that uses "nitrates". The nitrates are the end result of the cycle. This form of nitrogen, at low levels, isn't toxic to your fish. Over time, the level will increase and you'll need to perform a water change to remove the nitrates. I change half the tank water at least every 2 weeks. This is enough to keep the water safe for my fish.