Huge Unexplainable 12 Hour Nitrite Spike

[wonderer]

So I was completely under the impression my tank had cycled. I have been fishlessly cycling for three weeks now and with large amounts of nitrate and ammonia disappearing after 24 hours I thought I was good to go. This morning I woke up, did a random test and nitrite was through the roof, over 5ppm. Where it came from I don't know as I thought I was cycled, I have a constant good supply of nitrate as mentioned.

Tested midday again and it was halfway gone and tested again this evening, approx 12 hours after the first test and it had all gone, zero!! Where did it come from and where did it go so fast? I'm really worried about stocking now. If it did happen again in a stocked tank would 12 hours of those nitrite levels kill my fish? ( if it happened overnight for example)

Confused

 

[Chad]

Possibly a flaw with the test itself. In such cases I recommend testing again with a different test kit.

 

[TwoTankAmin]

Are you sure about saying nitrate above? Nitrate doesn't disappear overnight, you have to remove it.
 
Over 5 ppm of accumulated nitrite can not be dropped in the 12 hour or so time frame you indicated. If there are insufficient bacteria to prevent the nitrite build up to the level you state, they can not possibly reproduce fast enough to clear it anywhere near that quickly.
 
I would be a lot more worried that you reported impossible occurrences than about putting fish in the tank. At 3 weeks your cycle would be on the very shoort end of normal in the absence of seeding any bacteria or having many live plants. Have you read the site's article on Cycling Your First Tank?
 
In the absence of complete information about water parameters, ammonia dosing, tank size or virtually anything else, I have no clue what is going on in your tank. What has happened since day 1? Start with your tap water params and go from there. Include info about what dechlor you use, any other things you might be adding, all test readings from day one. Ammonia dosing details too. If you wonder if a piece of info is relevant or not, I would rather have some useless facts than be missing some useful ones

 

[wonderer]

Are you sure about saying nitrate above? Nitrate doesn't disappear overnight, you have to remove it.
 
Over 5 ppm of accumulated nitrite can not be dropped in the 12 hour or so time frame you indicated. If there are insufficient bacteria to prevent the nitrite build up to the level you state, they can not possibly reproduce fast enough to clear it anywhere near that quickly.
 
I would be a lot more worried that you reported impossible occurrences than about putting fish in the tank. At 3 weeks your cycle would be on the very shoort end of normal in the absence of seeding any bacteria or having many live plants. Have you read the site's article on Cycling Your First Tank?
 
In the absence of complete information about water parameters, ammonia dosing, tank size or virtually anything else, I have no clue what is going on in your tank. What has happened since day 1? Start with your tap water params and go from there. Include info about what dechlor you use, any other things you might be adding, all test readings from day one. Ammonia dosing details too. If you wonder if a piece of info is relevant or not, I would rather have some useless facts than be missing some useful ones

Sorry no I did not mean nitrate vanished overnight. I have been dosing ammonia at 3ppm for the past two weeks. It is always gone within 24 hours. My nitrate levels have always been around 30-40 ppm as I used filter media to help kick start the cycle. I have never seen any nitrites whatsoever since starting the cycle until this morning when it rocketed. That is why it surprised me, as I have always had nitrates and had used media I assumed I was further along and did not expect, and was told not to expect, a nitrite spike. Like I said though the nitrites have gone from at least 5ppm to zero within 12 hours today and nitrates have risen during those 12 hours to around 60 ppm. So at this point I have no idea where I am in the cycle. My high nitrates have led me to believe I was cycled, now im  jot so sure and worry about another spike if I stock.