# How to handle a nitrite spike in an established tank



## hollyfish2000 (Aug 23, 2007)

I'm in the middle of a post-water-change nitrite spike of undetermined origin. Tank is established. Ammonia was .25 but now 0. Nitrites ranging from .25 to 1 ppm. I've been frantically doing water changes twice a day to keep the level low, adding Dr. Tim's (to no avail, alas), swapped out one of the two filters for a filter on another established tank, and lowered the water level to keep a good splash and oxyenate the water.

It's a fully stocked 45-gallon African tank.

I've had no losses but the fish do breath heavily.

I'm about to swap out the second filter (a fluval 405) but the filter from the tank without the problem has soft pH and this one has hard. Does that negatively affect the biological colony? It would defeat the purpose if I swapped the filter and the existing colony didn't make it . . .


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## xxbenjamminxx (Jan 22, 2011)

I dont think that the PH would really matter to the bacteria, but am not totally sure on that one.

Best thing you can do is keep up on the water changes and you can add a little aquarium salt ( try 1 tablespoon per 10g to start) to the tank to help the fish deal with the nitrite and prevent poisoning.

HTH's


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## GaFishMan1181 (Dec 17, 2008)

How long has your tank been up and running?

My first thought is your tank was never fully cycled.
My second thought is if it was then did you remove all of the filter media?

Adding filter media from other established tanks will definitly help.

Have you ever tested your nitrates and did you have some?
Also what type of test kit?

I know its alot of questions but it will help figure out what happened. As far as what to do now. Personally i would try and get as much filter media from established tanks as possible. If you have a local store you trust ask if you can buy some. Also i wouldnt worry about the ph right now.

I've found changing the water does keep the levels down but it takes longer for the tank to get back to cycled stage. I'm not necessarly telling you to skip water changes but sometimes less is more.


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## prov356 (Sep 20, 2006)

> Tank is established.


How long has it been set up?

How long since it was first cycled?



> Ammonia was .25 but now 0. Nitrites ranging from .25 to 1 ppm.


So, ammonia spiked too?



> adding Dr. Tim's (to no avail, alas),


It won't immediately bring levels down, you have to give it a little time. Days, not hours.



> swapped out one of the two filters for a filter on another established tank,


Swapping out filters wasn't a good idea. Leave the filters alone.



> It's a fully stocked 45-gallon African tank.


What size tank?



> I'm about to swap out the second filter (a fluval 405)


Don't, leave the filters be.



> the tank without the problem has soft pH and this one has hard. Does that negatively affect the biological colony?


No, not like you mean. But, if the pH is very low, say below 6, the bacteria are inhibited and there may not be many in that filter. But, that's just a side note.

Much more info is needed, but basically continue the water changes and consider using Prime or Ammolock to detox ammonia/nitrite. Also, leave the filters be. Don't make any changes to the system.

Changing water does not inhibit cycling in an established tank. Do the water changes.


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## hollyfish2000 (Aug 23, 2007)

Tank is established -- two plus years established. Fully functioning 45-gallon tank with normal parameters until this week.

This is scenario:

30 percent water change Tuesday night using Prime
Wednesday morning noticed fish seemed to be breathing heavy. I did quick API ammonia and nitrite tests. Both were slight but measureable. I did immediate water change to bring down levels and later took the fluval 305 from this affected tank and swapped it for a fluval 305 from a different, also long-established tank, in order to bring bacterial colony into the tank experiencing the nitrite spike -- since measurable nitrite and ammonia told me the bacterial colony had failed for some reason. Ammonia quickly went to 0 and has stayed there.

Added Dr. Tim's Thursday night, but when nitrite was high this morning (Friday) I did another water change. While I know Dr. Tim's needs time, I did not want to subject fish to 1 ppm nitrite in the meantime. I did add another bottle this morning after the 50 percent water change.

At no time were any fiters opened or any media disturbed. Closed filter was simply unhooked from one tank and rehooked on other tank.

While doing the same with the Fluval 405 also on this tank would take all the filter-residing bacterial culture away from a different tank, that tank has a lot of plants and I'm thinking may be able to handle a disruption better than this African tank (with its higher pH) Why did one poster not recommend doing this?

Thank you for the salt recomendation. I"ll do that.
I am not "worried about the ph" except in the context of its possible effect on the bacterial culture if I move the filter from a 6.0 tank to a 7.8 tank


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## fox (Jun 11, 2009)

Curious if you medicated the tank or added any treatments to this tank a week or so prior to this measured spike?


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## prov356 (Sep 20, 2006)

I read it as 45 fish for some reason, not gallons. How many fish and what size, species then?

The bacteria colonies may just be overwhelmed from the increased bioload of fish that have grown out over the last two years. I wouldn't blame this on a water change. My guess is that it's been building over time and there are probably a few contributing factors involved. Going by what you've reported, there's no reason to beleive that the bacteria colony 'failed'. If the load overwhelmed one fluval 305, it'll overwhelm the other. Unless there's something different about or going on in that filter that we're unaware of.



> Why did one poster not recommend doing this?


Reason above. Unless you medicated or did something to wipe out the bacteria colony, I don't think that you have. These bacteria reside all over the system. The filter may not harbor as big of a percentage of them as you might think. Making too many changes too quickly can be disruptive in and of itself and exaggerate the problems. The water changes, detox, and Dr Tim's should have resolved it unless the bioload is just too much for the system now. And if that's the case, swapping filters isn't the answer.

But, just telling you what my approach would be. You're in front of it, so go with your gut on this, particularly if the fish are in jeopardy.


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## Chunkanese (Feb 4, 2011)

fox said:


> Curious if you medicated the tank or added any treatments to this tank a week or so prior to this measured spike?


This is what im guessing. Some products can kill bacteria colonies. Cleaning filter media to vigorously can send your tank back into a mini cycle. You may need to add a second filter to help out the bio load.


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## hollyfish2000 (Aug 23, 2007)

No medicine
No additional fish
No additions of any decorations.

Fish have grown slightly over two years, but were largely mature when put into tank. Their slight and slow growth over the years would not cause a large spike all of a sudden. Spike immediately followed a water change. I have had this happen once before. I wonder if I inadvertently didn't Prime one of the buckets. Others have suggested spring-time water might be the culprit.

BTW, I don't think I'm accurately conveying the filter situation. Tank has TWO filters -- a 305 and a 405 on it all the time. I do this on purpose so that in the event of exactly this type of scenario, I can remove one filter and swap with another filter on a different tank and thus easily and quickly "re seed" the tank. I did not add an additional filter to the tank -- I swapped one with an apparently damaged bacterial colony with one that has a fully functioning bacterial colony. Hopefully that clears that up!

with any luck when I get home tonight, the Dr. Tim's and the swapped out filter will have had time to bring down the nitrite. It already worked to eliminate the ammonia. Thanks for the good intentioned suggestions/solutions . . .


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## brinkles (Jan 30, 2011)

If there was ammonia in the tap water, prime is supposed to take care of it.


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## fox (Jun 11, 2009)

Do you use sand or gravel for the substrate? Sometimes sand can get a buildup of baddies which might hamper the BB. It is wise to "stir things up" occasionally with sand to help release these gas buildups.

If gravel the BB can colonize it and if you are too assertive with the vac you could decimate a primary colony. It is advised with gravel to not pay too much attention to any one area when doing maintenance to avoid this disruption.

Dr's Tims will give you a good base to start that colony again but you need to find what caused this condition in the first place so it is not repeated. Or it could just be a freak accident ...


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