Assuming your are doing a fish less cycle the nitrite spike could be huge. Nitrite-nitrate BB take longer to form and grow. I like to bring the nitrite down by WC to mid range on my test chart so I can monitor the progress. If it's currently off the chart then you can't see what is actually happening. Until the nitrite reliably falls to zero I keep feeding with ammonia to a low level, about 2ppm and control the nitrite as I said above.
Time it takes depends on many factors, low ph and low temp slow it down. Filter capacity and rate of flow can effect it too. I had a tank take 2 months and another 3 weeks. The 3 week tank had some seeded (dirty) filter media from the other tank put into the new filter. It made quite a difference.
Let us know how you are progressing and good luck.
