Fishless Cycle Was Finished... Until...

[MajorGFX]

Hi guys,

I am not a novice fish keeper but its been a few years since i kept Tropical fish.

About 3 months ago I purchased a 350L aquarium and started doing a Fishless cycle.

I followed this guide:

The (almost) Complete Guide and FAQ to Fishless Cycling

And it all went 'By the book' if you like until the last step! Now I am stuck!

Aquarium Details

350L Corner Tank
External UV Filter
Internal Fluval U4
Artificial Plants
Handful of Live Plants
Sand Substrate
No fish - Small amount of Snail infestation

I started a fishless cycle on my 350 litre tank 8 weeks ago, everything went as planned and last week I could turn 5ppm of ammonia into 0 ammonia 0 nitrite and 10 ammonia within about 8 hours. So i figured I had a very strong bio filter going on...

I did the last stage of the guide, a 90% water change just before I went to add fish and now I have nitrites off the chart! Why?!

I tested my Tap Water and its free from any Nitrites, Nitrates.

Ammonia is 0, Nitrites off the chart and nitrates 10. Ph is 7.6.

Why has Nitrites come back when I could turn it to 0 over night before?

I am assuming the large water change effected it somehow?

Any help would be hugely appreciated.

 

[ShinySideUp]

How odd.My only suggestion is that some of your snails have died and fallen into the substrate and when you poured in the new water it disturbed them, releasing ammonia into the water which the filter quickly changed to nitrites. It's a bit of straw-clutching though |I'm afraid.
 
My suggestion would be to whip out all the water, right down to the substrate and as much more as you can manage then try again.
 
Alternatively, wait until tomorrow morning and test for nitrites again, see if the filter has removed it.
 
Sorry can't be more help.

 

[MajorGFX]

I waited 24 hours and the Nitrites have not changed. I did a partial 50% water change and still nothing changed.

Surely the snails wouldnt create that much amonnia>Nitrite?
 
Thanks for your input its much appreciated.
 
PS - Bearing in mind I could add 5ppm of ammonia and change that to 0 in less than 12 hours.

 

[TwoTankAmin]

It is simple, that guide is off the mark and you have been adding way to much ammonia, This created too much nitrite and that stalled your cycle. Sky high nitrite can often show up as 0 on hobby test kits. The cycling article here is much more on the mark.
 
The bacteria do not die if they have no ammonia for days, it doesn't work like that.
 
Please watch this video by one of the researchers who helped identify the bacteria at work in aquariums. It deals with the test issue

 
1 ppm can convert into 2.55 ppm if nitrite. 5 ppm can turn into 12.75 ppm. At 16 or so ppm of nitrite the cycle starts to stall and the bacteria to die off. Higher is even worse. Dumping lots of ammonia into a tank doesn't make things go faster or better, it has the reverse effect.
 
The two major articles on fishless cycling that go back to the 1990s both were revised in terms of the ammonia dose.They both started at 5 ppm and are now in the 2-3 ppm range.

 

[MajorGFX]

It is simple, that guide is off the mark and you have been adding way to much ammonia, This created too much nitrite and that stalled your cycle. Sky high nitrite can often show up as 0 on hobby test kits. The cycling article here is much more on the mark.
 
The bacteria do not die if they have no ammonia for days, it doesn't work like that.
 
Please watch this video by one of the researchers who helped identify the bacteria at work in aquariums. It deals with the test issue

 
1 ppm can convert into 2.55 ppm if nitrite. 5 ppm can turn into 12.75 ppm. At 16 or so ppm of nitrite the cycle starts to stall and the bacteria to die off. Higher is even worse. Dumping lots of ammonia into a tank doesn't make things go faster or better, it has the reverse effect.
 
The two major articles on fishless cycling that go back to the 1990s both were revised in terms of the ammonia dose.They both started at 5 ppm and are now in the 2-3 ppm range.
 

 
So what shall I do now? Do a water change and leave it?
 
Just leave it?

 

[TwoTankAmin]

Did you watch the video?
 
Do as big a water change as possible. Test ammonia and right after you do the refill and have dechlored the water. If both still close to or at 0, use the ammonia calculator here to determine how much ammonia is need for your tank to get it to 3 ppm. Unless you know how much water is in the tank, reduce the advertised volume by about 15% and use that number for the volume you enter. This allows for substrate and decor.
 
Wait 24 hours and test and then report the results here.
 
 
Before doing the above you might want to try doing a diluted nitrite test to see if you do have off the charts nitrite.
 
[SIZE=13pt]Performing Diluted Nitrite Testing[/SIZE]
 
For this you need a way to create an accurate mix of your tank water and some amount of pure water, i.e. distilled or reverse osmosis/deionized (ro/di) water. You should be able to find a gallon of distilled water in the supermarket. Some fish stores sell ro/di water. You will need a clean measuring cup as well. You will use this to mix different solutions of tank and pure water to be able to test for nitrite. You do not want to use your tap water for dilution purposes as it will often contain things that can cause test result be inaccurate.
 
The reason for using a measuring cup is that it is important to get the proportions of the mix as close to dead on as possible. The advantage of measuring using a cup from which you will only use a few ml is that the potential for mixing errors is way less of an issue in 8 ounces than in 5 or 10 ml of water. What you will do is start by making a 50/50 mix (4 ounces each) of tank and pure water. Then you pour 5 ml of this into the little test tube and do the nitrite test. You will then multiply the result of the test by 2 to get the actual ppm in your tank.
 
However if this 50/50 diluted test result is still at the kit’s maximum level and the test kit reads to a maximum level of 8 ppm or less, you will have to do another further dilution. The easiest way is to start with ¼ cup of tank water and ¾ cup of pure water. Test this mix and multiply the result by 4 this time. Alternatively you can use ½ cup of the initial 50/50 mix and then add ½ cup of pure water to this. The result will be ¼ tank and ¾ pure water either way.

 

[MajorGFX]

Did you watch the video?
 
Do as big a water change as possible. Test ammonia and right after you do the refill and have dechlored the water. If both still close to or at 0, use the ammonia calculator here to determine how much ammonia is need for your tank to get it to 3 ppm. Unless you know how much water is in the tank, reduce the advertised volume by about 15% and use that number for the volume you enter. This allows for substrate and decor.
 
Wait 24 hours and test and then report the results here.
 
 
Before doing the above you might want to try doing a diluted nitrite test to see if you do have off the charts nitrite.
 
[SIZE=13pt]Performing Diluted Nitrite Testing[/SIZE]
 
For this you need a way to create an accurate mix of your tank water and some amount of pure water, i.e. distilled or reverse osmosis/deionized (ro/di) water. You should be able to find a gallon of distilled water in the supermarket. Some fish stores sell ro/di water. You will need a clean measuring cup as well. You will use this to mix different solutions of tank and pure water to be able to test for nitrite. You do not want to use your tap water for dilution purposes as it will often contain things that can cause test result be inaccurate.
 
The reason for using a measuring cup is that it is important to get the proportions of the mix as close to dead on as possible. The advantage of measuring using a cup from which you will only use a few ml is that the potential for mixing errors is way less of an issue in 8 ounces than in 5 or 10 ml of water. What you will do is start by making a 50/50 mix (4 ounces each) of tank and pure water. Then you pour 5 ml of this into the little test tube and do the nitrite test. You will then multiply the result of the test by 2 to get the actual ppm in your tank.
 
However if this 50/50 diluted test result is still at the kit’s maximum level and the test kit reads to a maximum level of 8 ppm or less, you will have to do another further dilution. The easiest way is to start with ¼ cup of tank water and ¾ cup of pure water. Test this mix and multiply the result by 4 this time. Alternatively you can use ½ cup of the initial 50/50 mix and then add ½ cup of pure water to this. The result will be ¼ tank and ¾ pure water either way.

 
I will do this tonight.
 
Its strange because when I had 0 reading on Nitrite and ammonia I did a 90% water change and added just 2 ppm of Ammonia. That is when it read off the chart, which is basically what I will be doing again tonight?
 
Lets try it anyway.
 
Thanks mate.
 
PS - Yes I watched it, thanks for your help.

 

[MajorGFX]

Here is an update:

I did a 95% water change and did a test straight after (about an hour) just out of curiosity and Nitrites were still off the chart? Couldn't understand why when I change nearly all the water.

I left it overnight and Nitrites went down to 0.5PPM by the morning.

I dosed up 2PPm of Ammonia and 24 hours later Ammonia 0, Nitrites more than 5PPM, Nitrates 40PPM. (Nitrates have increased compared to the past couple of weeks where it was 10PPM)

I think I am still cycling... Nitrites have been off the chart for 3 weeks now.

 

[MajorGFX]

Still adding 2PPM of Ammonia every 24 hours.
 
Nitrites still over 5PPM and Nitrates at 40PPM.
 
No change still, been 4 weeks + with Nitrites now

 

[daizeUK]

I don't think you should be adding 2ppm of ammonia every 24 hours.
To keep your ammonia-eating bacs fed you only need to add 1ppm of ammonia every 3-4 days.
The more ammonia you add, the more nitrite you create and the longer it will take to process all that nitrite you've been building up.
When your nitrite falls under 1ppm then you can add a full dose of 3ppm ammonia to test if all the nitrite will disappear within 24 hours.

 

[TwoTankAmin]

You are killing your own cycle. I do not have any idea who is advising you on how to cycle. The one thing I do know for sure is you are not following the directions here. I would suggest that you turn to whomever is telling you what to do since you appear inclined not to listen to what you are being advised here.
 
Every time you add 2 ppm of ammonia to your tank it creates 5+ ppm of nitrite.
 
The average cycle takes about 5-6 full doses (= 3 ppm) of ammonia plus the 1/3 snack dose. It takes about 5 weeks give or take. How many times have you added ammonia since you started cycling? How many times did you add more than 3 ppm?

 

[l_l_l]

Hi MajorGFX, solid advise given here!
Follow exactly the guides listed above and you will suceed!

 

[FishWithChips]

Hi,
 
Hope you have your issue solved by now.
 
If you think about it, by not adding ammonia, nitrites will not develop and eventually everything will be converted to nitrates if you keep doing regular water change.
 
Correct me if I am wrong. I might learn something valuable here before I start cycling my next tank which is a couple of days from now.

 

[Gruntle]

Correct me if I am wrong. I might learn something valuable here before I start cycling my next tank which is a couple of days from now.

I don't wish to tread on your toes, but I'm not sure about your statement about not adding ammonia. Adding too much ammonia means too much nitrites and your cycle stalls. Not adding any ammonia means your cycle never gets started in the first place.  If MajorGFX has a stalled cycle, waiting it out won't do anything except cause frustration because nothing is happening.
 
I followed the cycling article to the letter and had zero problems.