Possible to have missed nitrite spike?

[Shooter]

Currently ending day 12 of a fishless cycle. Ammonia levels were pretty high, so last night decided to replace some of the water and did about 20% of it. I tested ammonia again today and it's still fairly high, in the 7 - 8 range, and my nitrite test came out zero again, as usual. Here's the kicker though, I had read some other posts in various places of people missing their nitrite part of the cycle. I decided to do a nitrate test and lo and behold, I get a reading of 10 for nitrates. Did I miss the nitrite spike and am now cycled?? (I haven't tested nitrites every day, but fairly frequently.)
Any thoughts appreciated.

 

[FishDan]

If your ammonia is still so high, I would say probably not. It could be that nitrates are coming from your tap water. To be sure about that, test your tape water for nitrates and see. Generally though, your ammonia should also be 0 if your cycle were complete.

\Dan

 

[Shooter]

Sorry, I tested the tap water after I did these other tests and the tap comes out a very definitive zero for nitrates. I started the tank up, two days later I began the fishless cycling with addition of ammonia and a day or two later, got a plant to seed bacteria. I am ending day 12 right now. My thinking is that the high ammonia is due to my addition of ammonia and just overdid it a little and have a high concentration of ammonia. I didn't test for nitrites for about 4 or 5 days after starting ammonia and am wondering if I missed the nitrites in amongst that time? Could be that I have cycled, but the the bacteria cannot yet handle such a high concentration of ammonia? So, in summary, I stopped adding ammonia 3 days ago because the level had gotten up to around 8, nitrites continue to test out at zero, nitrates in tank water are 8 - 10, nitrates in tap water are zero.

 

[FishDan]

I'm not certain, but I would think that with the ammonia so high you still haven't finished cycling. Perhaps you are right and you did just over do the ammonia. Of course, if this is the case you have to wait until your ammonia reading is 0 before adding fish. Once you get your ammonia at 0, and if your nitrites remain 0 and you still show some nitrates I'd suspect your cycle completed. Normally, though, the nitrite phase is the longest, so it would be somewhat unusual that you'd miss it even if you didnt test for them for a few days.

\Dan