# Cycle stuck at elevated Nitrite level



## Don Ruslo (Aug 31, 2010)

Hello everyone!

I have a 36 gallon freshwater tank with about 25 small tetra/danios that is about a month and a half old. I did my first cycle a month ago or so with Zebra Danios and was able to see the complete cycle process with my API test kit.

For the last week or so I have been testing my water daily and I have been getting 0 Ammonia, 2 or 5 Nitrite, and 10 - 20 Nitrate.
The Nitrite level concerns me because it is very high (purple) and doesn't seem to be going down/converting quickly to Nitrate.

*Is it possible to get "stuck" midway through a cycle?*
Could this be due to adding too many fish after my first cycle?
I added no more than 10 fish/week

My fish are very active and seem healthy


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## jrman83 (Jul 9, 2010)

I guess your first cycle was on another tank? If it is the same tank, sounds like this tank never completed the cycle. If the cycle is complete then you should have 0 ammonia, 0 nitrite, and some value on nitrates.

How often have you been doing water changes? I would do a 25-30% change now and see what your values are after that. That small of a tank you shouldn't add no more than 2-3 a week, if they are tetra size. Bigger fish could change that.


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## NursePlaty (Feb 5, 2010)

*All I can say is give it time. Purple is high, you are right, I would do a 30%-50% water change before it hurts the fish. The nitrites should drop dramatically when its time. I remember 3 weeks ago, my 29g had purple readings also so I did a water change, retested a week later and it was light blue.*


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## Don Ruslo (Aug 31, 2010)

Thanks for the replies guys!

My first cycle was on this tank (the 36 gallon). Over the course of 4 days or so starting at readings of zero all across the board, I watched my Ammonia rise, then Nitrites, then Nitrates. It was textbook. Then I did a 15-20% water change when my levels stabilized at zero except for a moderately elevated Nitrate (The cycle was complete).

Other than this water change at the end of my first cycle (approximately 3-4 weeks ago), I have not done any water changes. *Even in a well established tank you will be able to read via testing the chemical changes during cycling right? *

I think I will do a water change now as you suggested and then check my levels...

After my first cycle, I added on average 5 small tetras a week.


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## jrman83 (Jul 9, 2010)

Yes, you'll still be able to read chemical changes.

A couple of things....I wouldn't go more than 10 days without a partial water change. At least in the 15-25% range. With the amount of fish you have in there, water quality could easily degrade over long periods between water changes. Just a recommendation.

Given the size of your tank if I added more than one or two fish in a week, I'd want to check at least for ammonia for the first few days after I added them and be prepared to deal with rising levels if necessary. I recently finished a fishless cycle on a 125g tank and when I added fish, I added 45 fish all at once. After the cycle ended I added ammonia purposely to test the bio filter to see how long it took to take all readings back to normal, so I knew my tank could handle it. But, I still tested for ammonia the first 4-5 days just to stay ahead of it. Just something to think about when adding fish. Smaller tanks can be impacted negatively with even a little change in the bio load.


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## Don Ruslo (Aug 31, 2010)

Just for the record...
Plus I like pictures


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## tazzapooj (Sep 20, 2010)

thats the kit i have there, think im at the end of my cycle but my nitrite and nitrate levels have gone through the roof today!!!


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## Don Ruslo (Aug 31, 2010)

Ok. Just did about a 13 gallon water change (My tank is a 36 gallon).
After waiting 5 or so minutes I tested my water again and *my Nitrites are at about the same level...slightly lower if any!*

I figured it would dilute the Nitrite level significantly...does it take time?


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## jrman83 (Jul 9, 2010)

Do you mean nitrite? Wait a couple of hours and test again. If it still persist, do the same thing tomorrow. Repeat until the levels get to 1 or below. That's what I'd do.


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## Don Ruslo (Aug 31, 2010)

Yes!! I meant Nitrites not Nitrates...my post above has been edited to be correct now.

Ok. I will keep doing daily water changes until my levels are below 1.0 on the API scale pictured above. Shouldn't they ideally be zero (light blue) though?

It's kinda funny...I used my gravel cleaner siphon to remove the water for the water change...immediately when I started my 3 or 4 Ghost Shrimp came out and started going crazy! It's like they thought it was their chance to take over the world


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## jrman83 (Jul 9, 2010)

Nitrites will be 0 once your tank is cycled. Once you get them down to a certain level they should disappear on their own.


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## Don Ruslo (Aug 31, 2010)

Excellent! And I assume that once I get the Nitrite level low enough (like you say) that that it will quickly disappear and drop to zero BECAUSE my Nitrospira bacteria (that is apparently struggling) will catch up and be able to do its job?


I have resisted adding any SeaChem Stability, SeaChem Prime, or Tetra Safe Start (TSS) to my tank because I would like to fix this little problem without potentially creating another later down the road...


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## Don Ruslo (Aug 31, 2010)

I just did another ~50% water change...this is the second one in two days.

An hour later and my Nitrites are STILL relatively high (purple)!!
It's like the water changes are not having any effect! Ammonia and Nitrates are still minimal.

I will continue doing daily 50% water changes I guess....I just figured that a water change that large would have significantly reduced the Nitrite level already.....


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## jrman83 (Jul 9, 2010)

Keep going. It will get to a readable level soon.

I guess your fish are doing well?


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## beaslbob (May 29, 2009)

Stop adding food until nitrItes drop down.


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## Don Ruslo (Aug 31, 2010)

Yes. My fish seem to still be doing well and are still active. I am carefully looking for signs of disease... 

I will stop feeding...


Thanks for all the help everyone!!


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## Don Ruslo (Aug 31, 2010)

Would it be acceptable to change my filter right now? 
After taking a look at it...It seems to have a coloration to it that looks like the flake food that I feed...this makes me think there is a large amount of tiny food particles that are stuck to the back of the filter...

*Should I change my filter?*


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## jrman83 (Jul 9, 2010)

NO! When you do your next water change wash it out in the tank water and put it back. If you change the filter you will loose most of the newly formed bacteria that is in your tank - the good and the bad. After your cycle is complete, you can start to change out pieces of your filter system if you like, just don't change out all pieces at one time. Separate them.


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## Don Ruslo (Aug 31, 2010)

Do you mean wash it out in the tank water that I am removing? Or the tank water that is actually IN the tank??

Thanks again for all your help


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## Cole (Aug 18, 2010)

In the water that you have removed. You don't want to clean it with regular tap water because the chlorine will kill the bacteria.


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## jrman83 (Jul 9, 2010)

Don Ruslo said:


> Do you mean wash it out in the tank water that I am removing? Or the tank water that is actually IN the tank??
> 
> Thanks again for all your help


Most of your beneficial bacteria is in your gravel and your filter. Chlorinated water will kill it as was mentioned. Just keep this in mind when doing your filter maintenance.

What kind of filter is it?


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## Don Ruslo (Aug 31, 2010)

My filter is the Aqueon "Power Filter 30" that came with my tank kit. It the "Large" Aqueon filter cartridges.

Here in a little bit when I do another water change (after I tesst my water of course), I plan to briefly take out and clean my filter cartridge in some of the water I removed form the tank...just to get rid of some of the food particles that are stuck in the filter.


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