Fishless Cycling - Impossibly High Nitrites?

HI all,

First off, a big thanks to all users on the site. Fishlore has been an invaluable resource so far in me getting up on my feet with a planted aquarium!

I've done quite a lot of reading across multiple forums to try and understand my present scenario, but I thought I'd make a post here to see what others might have to say.

My set-up:
Juwel Rio 180 (180L/47g)
Bioflow M in-tank filter
Eco Complete Substrate
2*23W LED
2*Anubias
4*Monte Carlo
2*C. Becketii
2*C. Wenditii
1*Amazon Swords
2*Drift wood
4*Java moss
No CO2 injection (yet!)

Ferts/additives:
Flourish Comprehensive 5ml once per week
1*Flourish Root Tabs
Flourish Excel 5ml once every second day
API Tap Water Conditioner
Seachem Stability 11.25ml once per day
(Note: I've just purchased a whole set of macro ferts today to remedy their omission)

A few parameters:
Ph: 6.8
Gh: 5
Kh: 3
Ammonia: 0
Nitrite: Impossibly high!
Nitrate: >40 80<

My problem: I've been dosing 2ppm ammonia with Dr Tim's, and it's being reliably cycled within 24 hours. Nitrites are being converted to nitrates as well. However, the nitrites seem impossibly high given that I've only dosed ~5.5ppm ammonia in total over the past 6 days. In fact, I haven't dosed ammonia over the past 2 days to prevent a nitrite build up.

Please see the attached photo of my nitrite tests using the API liquid test kit.

The tube on the left is undiluted, while the tube on the right has been 95% diluted with deionised water. I had to resort to a 95% dilution as 80%, 90% dilutions didn't seem to modify the resulting colour at all in comparison to undiluted nitrite sample.

Are my nitrites that high? Is something else contributing to the ammonia levels given that I haven't added that much? I tested my tap water and the ammonia level is 0.25ppm. Am I interpreting the colours incorrectly? If so, is there a reason why the 80% and 90% dilutions didn't seem to result in lighter colours?

At this stage, I'm contemplating a large (95%) water change to bring the nitrite/nitrates down.

 

No even though there is a presence of nitrAtes you may not have enough of the previous bacteria to process that much nitrites... but if your ammonia is 0 you MUST keep adding the dr Tim’s and keep bringing that ammonia up to at least 2 ppm... then one day your nitites will just disappear... it’s the longest wait period usually as these are the slower bacteria- takes longer to build them up... but if you cut out your ammonia you will break the chain (imagine it like a circle)... during your nitrite spike they will go off the charts for a while... then once they are 0 you will get a nitrate spike and then everything should be at normal levels once they drop... but always keep bringing your ammonia up to min.. 2ppm (possibly more depending on what your bioload will be when you add fish) but I wouldn’t go higher then 4ppm
Hope that helps and makes sense...
But it’s perfectly normal for your nitrites to be off the chart for up to a couple weeks

 

But it’s perfectly normal for your nitrites to be off the chart for up to a couple weeks

HI Francine, thanks for your response! I've read a lot of conflicting information about whether the ammonia oxidising bacteria require an uninterrupted diet of NH4Cl lest they die off. At this stage, I'm concerned about the cycling process stalling due to unacceptably high nitrites, so I cautiously stopped dosing ammonia. Even then, I've read conflicting information about whether excessive nitrites do in fact cause a cycle stall.

I've tried a more comprehensive nitrite test and I've attached a photo of the results for those interested. From left to right: undiluted, 50% diluted, 90% diluted, 95% diluted. I think laying it all out as a sequence has made it easier for me to distinguish the colours: I think I'm sitting at around 10 ppm nitrates.

I'll dose a smaller amount of ammonia tonight and keep watch on the nitrites.

 

No part of the nitrogen cycle is 100% a high high rise in nitrites... it comes right after your ammonia is able to process.. but you need to keep the ammonia like I said at 2ppm and make sure it continues to drop back down within 12-24 hours.. you will have these high high nitrites and then one day (when you finally feel like you’re ready to scream! Lol) they will just drop off... then the next bacteria will start to build up which is your nitrate transferring bacteria... they will also sky rocket and then drop down to around 20... once you have consistent readings of 0,0, and around 20ish... your cycle is done sometimes this part feels like waiting forever and other times it’s quicker... when your testing and you add your drops if they automatically turn purple as soon as hitting the water in the tube they are still off the charts and no need to even wait out the 5 minutes... I’ve had sucess using stability while I’m cycling but have done it both with and without... but it may help boost your growth of the bacteria

it can take anywhere from weeks to months to get a cycle going properly

 

Nitrites are usually about 3X the ammonia.

 

HI Francine, thanks for your response! I've read a lot of conflicting information about whether the ammonia oxidising bacteria require an uninterrupted diet of NH4Cl lest they die off. At this stage, I'm concerned about the cycling process stalling due to unacceptably high nitrites, so I cautiously stopped dosing ammonia. Even then, I've read conflicting information about whether excessive nitrites do in fact cause a cycle stall.

I've tried a more comprehensive nitrite test and I've attached a photo of the results for those interested. From left to right: undiluted, 50% diluted, 90% diluted, 95% diluted. I think laying it all out as a sequence has made it easier for me to distinguish the colours: I think I'm sitting at around 10 ppm nitrates.

I'll dose a smaller amount of ammonia tonight and keep watch on the nitrites.

Sorry how do you know it’s 10? When the test doesn’t go that high? You could be at 5 or 6.... to me it looks like 5 or higher but I’m not understanding how you are guessing 10? Which can be perfectly normal

 

but I’m not understanding how you are guessing 10

It was recommended here and in other forums to increasingly dilute the tank water samples in order to show a low range reading, from which can be derived a high range estimation for the tank's nitrite levels.

My photo perhaps doesn't capture it well, but the right-most tube on the 2nd photo is 0.25ml tank water diluted with 4.75ml deionisied water. To me, the colour appeared closest to 0.5 ppm nitrite. Since the sample is 95% diluted (in other words, 1/20th the concentration of the tank water), I can derive an approximate reading of 10 ppm nitrite for the tank as a whole from the sample.

 

Well that’s odd... I’m not be any means saying it’s not right I just have never ever heard of doing that... part of the cycle is that the nitrite HAS to sky rocket and like I said both myself and many others this has lasted weeks and weeks sometimes even well over a month... this is usually the longest part of the wait....a tank can take anywhere from like a week or 2 to months to fully cycle... I know it’s hard to wait because you are so anxious lol... you can always do a water change.... there are no bacteria at all living in your water... it’s all in the substrate, walls of tank, ornaments, plants and mostly in your filters biological section... what is in your filter for bio anyway? I can’t rememeber if you mentioned... but if you do a water change... make sure to test your water after and bring your ammonia back up to 2ppm... then wait 12-24 hours and test again... make sure your ammonia has come back down to 0 and test just your nitrites... if they are still high then you don’t have enough bacteria yet and it’s just waiting and testing both ammonia and nitrites everyday... and make sure that your ammonia stays around 2 every time you check it and it drops...and one day... I promise your nitrites will just disappear... once they disappear then check your nitrAtes... that part can often rise and fall without you even seeing it... but your levels need to be 0,0 and around 20.... have you ever tested your tap water with the kit to see if it’s all normal?

 

HI all,

First off, a big thanks to all users on the site. Fishlore has been an invaluable resource so far in me getting up on my feet with a planted aquarium!

I've done quite a lot of reading across multiple forums to try and understand my present scenario, but I thought I'd make a post here to see what others might have to say.

My set-up:
Juwel Rio 180 (180L/47g)
Bioflow M in-tank filter
Eco Complete Substrate
2*23W LED
2*Anubias
4*Monte Carlo
2*C. Becketii
2*C. Wenditii
1*Amazon Swords
2*Drift wood
4*Java moss
No CO2 injection (yet!)

Ferts/additives:
Flourish Comprehensive 5ml once per week
1*Flourish Root Tabs
Flourish Excel 5ml once every second day
API Tap Water Conditioner
Seachem Stability 11.25ml once per day
(Note: I've just purchased a whole set of macro ferts today to remedy their omission)

A few parameters:
Ph: 6.8
Gh: 5
Kh: 3
Ammonia: 0
Nitrite: Impossibly high!
Nitrate: >40 80<

My problem: I've been dosing 2ppm ammonia with Dr Tim's, and it's being reliably cycled within 24 hours. Nitrites are being converted to nitrates as well. However, the nitrites seem impossibly high given that I've only dosed ~5.5ppm ammonia in total over the past 6 days. In fact, I haven't dosed ammonia over the past 2 days to prevent a nitrite build up.

Please see the attached photo of my nitrite tests using the API liquid test kit.

The tube on the left is undiluted, while the tube on the right has been 95% diluted with deionised water. I had to resort to a 95% dilution as 80%, 90% dilutions didn't seem to modify the resulting colour at all in comparison to undiluted nitrite sample.

Are my nitrites that high? Is something else contributing to the ammonia levels given that I haven't added that much? I tested my tap water and the ammonia level is 0.25ppm. Am I interpreting the colours incorrectly? If so, is there a reason why the 80% and 90% dilutions didn't seem to result in lighter colours?

At this stage, I'm contemplating a large (95%) water change to bring the nitrite/nitrates down.

HI Francine, thanks for your response! I've read a lot of conflicting information about whether the ammonia oxidising bacteria require an uninterrupted diet of NH4Cl lest they die off. At this stage, I'm concerned about the cycling process stalling due to unacceptably high nitrites, so I cautiously stopped dosing ammonia. Even then, I've read conflicting information about whether excessive nitrites do in fact cause a cycle stall.

I've tried a more comprehensive nitrite test and I've attached a photo of the results for those interested. From left to right: undiluted, 50% diluted, 90% diluted, 95% diluted. I think laying it all out as a sequence has made it easier for me to distinguish the colours: I think I'm sitting at around 10 ppm nitrates.

I'll dose a smaller amount of ammonia tonight and keep watch on the nitrites.

Nitrobacter naturally grow after Nitrosomas because they have to produce nitrates for Nitrobacter to eat so of course the ammonia will have to be changed first. But if you stop adding ammonia, you'll starve the Nitrosomas to death. Don't worry about the high nitrites. Once they change to nitrates, you can lower nitrates by partial water changes.

 

Iyou could do a big water change to get the nitrite to 5 or below as I understand above that can stall the cycle. But keep dosing ammo to 2ppm. One day, your nitrite will just disappear.

 

Yup you don’t want to stall but you don’t want it not present at all... so it’s a fine line... did you say you were using Dr Tims for your ammonia source? If so it’s easy to overdose that stuff... just because it comes out so quickly.. especially if you have a big tank and need to add 100’s of drops lol

 

I know a lot of folks say just let the nitrites work themselves out but water changes will speed the process up.

The last time I cycled a tank (55 gallon) from scratch (fish in cycle so a steady source of ammonia) my nitrites, like yours, one day jumped from nothing to off the chart. Since lives were at stake I was doing daily water changes to get those nitrites down. I did a 30% water change daily for 5 days in a row. (before the spike I was doing 30% every other day). I tested for nitrites after each daily water change. For 4 days it remained off the chart. After the 5th one the nitrites were zero and that is where they have remained.

Some folks think water changes will disrupt the cycling process but that has never been my experience. The only way it would is if untreated water was used if one has chlorine in their source water. The bacteria we are trying to grow doesn't live in the water. It grows on all the surfaces but mostly on the filter media. Removing some water and replacing it with fresh will help balance the spikes.

The most important thing one must do is keep a steady ammonia source. It is the beginning of the cycle. Without it the cycle stalls and dies. If it drops to zero and stays there the bacteria will start to die off. Personally I would add more any time it dropped down to .25 Dosing it back up to 2 each time it drops to .25 will keep the bacteria fed and thriving.

 

did you say you were using for your ammonia source?

The most important thing one must do is keep a steady ammonia source.

The instructions on Dr Tim's website reads: "Generally during a fishless cycle one needs to add ammonium chloride to their tank 3 or 4 times..." with a recommended dose of 2 ppm.

I think Dr Tim's advice of infrequent ammonia dosings is based on an understanding that nitrosomonas don't rapidly die off in ammonia deprived conditions: they alter their metabolism or enter dormancy and they readjust once ammonia is reintroduced.

But again, for every forum post that I've read which says "nitrosomonas don't die!" there's another that reads "keep feeding your nitrosmonas or else they'll die!"

At this stage, since ammonia's been at 0 for 3 days, I've made a small 1 ppm dose of ammonia. For what it's worth, my nitrosomonas colonised the aquarium quite quickly: it took 4 days for it to start reliably processing 2 ppm ammonia in 24 hours. Based on my rough guesstimations, I think the tank's currently processing about 1 ppm nitrite per 24 hours.

 

I think Dr Tim's advice of infrequent ammonia dosings is based on an understanding that nitrosomonas don't rapidly die off in ammonia deprived conditions: they alter their metabolism or enter dormancy and they readjust once ammonia is reintroduced.

I am not a scientist and maybe they don't die as quickly as thought but if one is trying to cycle a tank why would they want to allow the bacteria to go dormant. As long as there is an ammonia source the bacteria will continue to grow and the tank will complete the cycle.

 

why would they want to allow the bacteria to go dormant.

I'm certainly not a marine biologist either! This is how I make sense of it: once you've added a few 2 ppm doses of ammonia and your ammonia oxidising bacteria have converted it to nitrites, then it's just a matter of waiting for your nitrite oxidising bacteria to colonise and convert the nitrites to nitrates. In the mean time, there isn't as pressing a need to continue dosing significant amounts of ammonia because (1) the existing nitrosomonas colony is unlikely to die in a matter of a few weeks; (2) any further ammonia will just result in a greater nitrite ppm, leading either to a longer cycle time until 0 nitrite ppm or necessitating large water changes to dilute nitrite levels.

 

Please keep us updated on your progress. It would be interesting to see if the cycle will in fact complete while not adding a steady source of ammonia.

 

Ya I think you’re going to run into issues with no ammonia... and you can do as many water changes as you want... no bacteria live there...

 

Please keep us updated on your progress. It would be interesting to see if the cycle will in fact complete while not adding a steady source of ammonia.

HI all,

First off, a big thanks to all users on the site. Fishlore has been an invaluable resource so far in me getting up on my feet with a planted aquarium!

I've done quite a lot of reading across multiple forums to try and understand my present scenario, but I thought I'd make a post here to see what others might have to say.

My set-up:
Juwel Rio 180 (180L/47g)
Bioflow M in-tank filter
Eco Complete Substrate
2*23W LED
2*Anubias
4*Monte Carlo
2*C. Becketii
2*C. Wenditii
1*Amazon Swords
2*Drift wood
4*Java moss
No CO2 injection (yet!)

Ferts/additives:
Flourish Comprehensive 5ml once per week
1*Flourish Root Tabs
Flourish Excel 5ml once every second day
API Tap Water Conditioner
Seachem Stability 11.25ml once per day
(Note: I've just purchased a whole set of macro ferts today to remedy their omission)

A few parameters:
Ph: 6.8
Gh: 5
Kh: 3
Ammonia: 0
Nitrite: Impossibly high!
Nitrate: >40 80<

My problem: I've been dosing 2ppm ammonia with Dr Tim's, and it's being reliably cycled within 24 hours. Nitrites are being converted to nitrates as well. However, the nitrites seem impossibly high given that I've only dosed ~5.5ppm ammonia in total over the past 6 days. In fact, I haven't dosed ammonia over the past 2 days to prevent a nitrite build up.

Please see the attached photo of my nitrite tests using the API liquid test kit.

The tube on the left is undiluted, while the tube on the right has been 95% diluted with deionised water. I had to resort to a 95% dilution as 80%, 90% dilutions didn't seem to modify the resulting colour at all in comparison to undiluted nitrite sample.

Are my nitrites that high? Is something else contributing to the ammonia levels given that I haven't added that much? I tested my tap water and the ammonia level is 0.25ppm. Am I interpreting the colours incorrectly? If so, is there a reason why the 80% and 90% dilutions didn't seem to result in lighter colours?

At this stage, I'm contemplating a large (95%) water change to bring the nitrite/nitrates down.

It's ok to do some water changes to get the nitrites down, but add your ammonia suppliment after the water change.

 

It's ok to do some water changes to get the nitrites down, but add your ammonia suppliment after the water change.

Yes I’ve reiterated to him several times about keeping his ammonia at at least 2ppm every time it comes down

 

Ya I think you’re going to run into issues with no ammonia... and you can do as many water changes as you want... no bacteria live there...

Yes I’ve reiterated to him several times about keeping his ammonia at at least 2ppm every time it comes down

Thanks Francine. I did take notice of your recommendations. The problem is that there's a lot of contradictory information available from both experienced aquarists such as yourself and product manufacturers.

For e.g., Seachem advises on their official forums not to change the water during the first week or two when using Stability as much of the introduced bacteria is still suspended as a solution. Seachem also recommends witholding ammonia when nitrites spike especially high to prevent a backlog of nitrite building up. In addition, as I've mentioned earlier, Dr TI'm recommends infrequent doses of ammonia, presumably for the same reason: to avoid an excess of nitrite that would either prolong the cycling process or require substantial water changes.

I am continuing to dose ammonia, but at a reduced rate of 1 ppm every other day until the nitrites settle down. I dosed 1 ppm 12 hours ago, and a test just then confirmed that the ammonia level is now 0. This is comparable to 3 days earlier (when I had stopped dosing ammonia) when 2 ppm of ammonia was being processed to 0 in 24 hours. So over the 3 days in which I didn't dose ammonia, it seems that my nitrosomonas colony didn't die, or at least didn't die to the point where its ammonia oxidising capacity was significantly compromised. This seems like a good compromise at this stage.

 

Here is where your problem is going to lie... if your only dosing to 1ppm when you add your fish you are going to run into big troubles because the amount of bacteria won’t be able to handle your bioload unless you add like 2 fish at a time and even 1 fish like a pleco could throw that out of wack... what you need to do with dr tims... it explains right on the back of the bottle how many drops you need per gallon (4) and you add that many drops for how big your aquarium is... so if your aquarium is 20 gallons you add 4 drops x 20 gallons= 80 drops... that will bring your ammonia to 2ppm
And the reason why they tell you with stability not to do a water change is because there bacteria spores take time to work... therefore changing the water won’t give them enough time to do their job but you don’t need stability anyway... all you need is an ammonia source and keep adding it the same every time it drops until your nitrites drop to 0 and stay at zero for several days.. even a week (but during this time you must still add ammonia) until you put fish in there you have to add ammonia... once the fish are in they are your ammonia source

 

Here is where your problem is going to lie

I think you're misinterpreting my posts. I'm not dosing 1 ppm permanently or acclimating my nitrosomonas colony based on a 1 ppm ammonia bioload. I'm only dosing reduced ammonia at this stage in order to reduce the nitrite backlog that the nitrobacter is required to process.

When the nitrite levels reduce below 5, I'll resume 2 ppm dosing.

Regarding Dr Tim's instructions, if you peruse their website you'll find that they also publish a more comprehensive guide for using their ammonium chloride solution and nitrifying bacteria product in fishless cycling. Dr TI'm recommends that ammonia is only added on day 1, 3 and 6 of a 14 day cycling timeframe. In addition, Dr TI'm only recommends adding ammonia on those days when both ammonia and nitrite readings are below 1 ppm.

 

Ya I don't follow what’s on the website I just follow the bottle instructions and yes I apologize I did misinterpret... I just didn’t want you to only dose 1ppm then add fish and have crazy spikes.... quite honestly I have seen this nitrite stage last for months... for some reason some tanks just tend to be stubborn but you will get there and your fish will be happy and healthy... it’s hard when everyone has a different way of doing things.... and everyone has this own way... I hope you can get your fishies in there soon!!!

 

yes I apologize I did misinterpret

No need to apologise! I don't think my posts were all that clear (which is a common occurrence since I always seem to post early in the morning when I'm barely awake!).

it’s hard when everyone has a different way of doing things.... and everyone has this own way... I hope you can get your fishies in there soon!!!

You're absolutely right: everyone seems to have their own way to go about things and it works for them. And of course, I really do appreciate you and everyone posting their thoughts and experiences! It helps me get an idea of what works for others, and what I ought to try to see if it works for me when it comes to my own aquarium.

 

The problem with long posts like this one is that one loses the point of reference. This is what I would do...

1. Do a 50% water change. Immediately after the water change do the tests for ammonia, nitrites and nitrates.
2. Add 2ppm of Dr Tims. Test after 12 hours. You will need to see the 2ppm move to nitrites.
3. After another 12 hrs, do the tests again. This time you should see the nitrites move to nitrates.

So within 24 hrs, whatever you put in as ammonia, should transfer to nitrites and then nitrates. Don't pay too much attention as to weather it is 2 x nitrites / ammonia or any others variable as the number will differ based on a number of factors.

What is important for you is to move ammonia to nitrites and nitrites to nitrates within a 24hr cycle........ and you need to see that move to determine if your tank is cycled with "ZERO" inhouse load.

You have a planted tank, so if the plants are showing signs of good growth, then they will use up the nitrates.

If your nitrites are not converting to nitrates, just do water changes daily ~20-25%. This will keep nitrites low and since you have ammonia in your water, will provide a source of ammonia for your ammonia oxidising bacteria. Test twice a week. Once the nitrites drop, you can slow down with water changes and do the 1-2-3 steps I described above.
Good luck and keep us updated.
btw, my planted 125g tanks took over two months to cycle - fishless. Patience.....patience is what it sometimes takes.

 

I thought I'd provide an update for those interested.

My historical ammonia parameters are as follows:

July 3: started dosing with 2 ppm of ammonia, processed to 1 ppm in 48 hours
July 5: dosed 1 ppm of ammonia, processed to 0.5 ppm in 24 hours
July 6: dosed 1.5 ppm of ammonia, processed to 0 ppm in 24 hours
July 7: dosed 1 ppm of ammonia, processed to 0 ppm in 24 hours
July 9: 2 days of no ammonia, dosed to 1 ppm, processed to 0 ppm in 24 hours
July 15: 6 days of no ammonia, dosed to 2 ppm, processed to 0 ppm in 48 hours
July 18: 3 days of no ammonia, dosed to 2 ppm, processed to 0 ppm in 24 hours

In addition, the resultant nitrite is being processed to 0 ppm within 42 hours. This is a vast improvement from a week ago when nitrite was static at >5 ppm for days at a time.

I did let my ammonia sit at 0 ppm for several days at a time to prevent a nitrite backlog. While the nitrosomonas colony did require a bit of time to re-acclimate when I began dosing 2 ppm ammonia again, it didn't seem as if there was a massive die-off or cycle stall as is often hypothesised.

However, I did do a large (75%) water change before dosing ammonia on July 15. While it was mostly to reduce the build up of ferts and tannins, it seems a bit of a coincidence that my nitrobacter colony suddenly began working overtime and processing the nitrites quite quickly.

 

I thought I'd provide an update for those interested.

My historical ammonia parameters are as follows:

July 3: dosed 2 ppm ammonia, processed to 0 ppm in 24 hours
July 9: 6 days of no ammonia, dosed to 1 ppm, processed to 0 ppm in 24 hours
July 15: 6 days of no ammonia, dosed to 2 ppm, processed to 0 ppm in 48 hours
July 18: 3 days of no ammonia, dosed to 2 ppm, processed to 0 ppm in 24 hours

In addition, the resultant nitrite is being processed to 0 ppm within 42 hours. This is a vast improvement from a week ago when nitrite was static at >5 ppm for days at a time.

I did let my ammonia sit at 0 ppm for several days at a time to prevent a nitrite backlog. While the nitrosomonas colony did require a bit of time to re-acclimate when I began dosing 2 ppm ammonia again, it didn't seem as if there was a massive die-off or cycle stall as is often hypothesised.

However, I did do a large (75%) water change before dosing ammonia on July 15. While it was mostly to reduce the build up of ferts and tannins, it seems a bit of a coincidence that my nitrobacter colony suddenly began working overtime and processing the nitrites quite quickly.

Actually it's the nitrosomas turning the ammonia into nitrites. You are lacking nitrobacter sufficient enough to change the nitrites into nitrates. You cannot grow nitrobacter at all until the nitrosomas make nitrates for them to feed on. So unfortunately, you need to keep the nitrosomas alive by keeping a daily source of ammonia for them... which will become more nitrites. You need to continue an ammonia source daily and just do smaller water changes, like 25 percent every couple of days until the nitrites turn into nitrates. Since the ammonia processing has to make nitrites first, it takes quite awhile for the nitrobacter to start growing after the nitrosomas have begun weeks ahead at their job of making nitrites. So until your nitrobacter catch up to the nitrosomas, what you're going through during the development of the cycling process is inconvenient but normal.

 

I thought I'd provide an update for those interested.

My historical ammonia parameters are as follows:

July 3: dosed 2 ppm ammonia, processed to 0 ppm in 24 hours
July 9: 6 days of no ammonia, dosed to 1 ppm, processed to 0 ppm in 24 hours
July 15: 6 days of no ammonia, dosed to 2 ppm, processed to 0 ppm in 48 hours
July 18: 3 days of no ammonia, dosed to 2 ppm, processed to 0 ppm in 24 hours

Unique and interesting way of doing it but I don't understand why you went days without feeding your cycle.

In addition, the resultant nitrite is being processed to 0 ppm within 42 hours. This is a vast improvement from a week ago when nitrite was static at >5 ppm for days at a time.

If you are still registering nitrites it just means that they have not receive sufficient food to go quickly/almost instantly to nitrates. Nitrites should spike at some point and then drop to zero. Once that happens one should never see nitrites again in a cycled tank. If they do show up then that is a sign that something about the cycle is out of balance.

I did let my ammonia sit at 0 ppm for several days at a time to prevent a nitrite backlog. While the nitrosomonas colony did require a bit of time to re-acclimate when I began dosing 2 ppm ammonia again, it didn't seem as if there was a massive die-off or cycle stall as is often hypothesised.

This result is very interesting. It is good to know that the bacteria didn't die off without an ammonia source for a few days. I suspect instead of dying it just went semi-dormant while waiting for food.

However, I did do a large (75%) water change before dosing ammonia on July 15. While it was mostly to reduce the build up of ferts and tannins, it seems a bit of a coincidence that my nitrobacter colony suddenly began working overtime and processing the nitrites quite quickly.

Not actually a coincidence. This is what I recommend doing whenever a tank seems to be stalled at one point or another during the cycling process. A water change will almost always jump start a stalled cycle.

 

I realised that I made some errors in my original post regarding the schedule of dosages. I've expanded it cover all my ammonia doses right from the beginning.

You cannot grow nitrobacter at all until the nitrosomas make nitrates for them to feed on... So unfortunately, you need to keep the nitrosomas alive by keeping a daily source of ammonia for them... which will become more nitrites.

Unique and interesting way of doing it but I don't understand why you went days without feeding your cycle.

I should've clarified that at no time in my cycling so far has nitrite sat at 0 ppm for longer than 24 hours. Ammonia is being oxidised quite quickly, and it only required approximately half a week from the start of ammonia dosing for my nitrosomonas colony to begin processing 2 ppm of ammonia into nitrite within 24 hours.

The initial issue for me was that nitrite levels peaked at >10 ppm within 5 days of my cycle and remained static for a week or so. This to me was an indication that the nitrite oxidising bacteria (nitrobacter and nitrospira) wasn't metabolising efficiently and/or wasn't growing well.

At that stage, there didn't seem any particular reason to continue dosing ammonia seeing that:

1. The nitrosomonas colony had already been established and that ammonia oxidising bacteria don't die off rapidly in the absence of ammonia (as an example, see Dr Tim's guide on fishless cycling where there's a several day gap in between many of the ammonia doses);
2. The nitrite oxidising bacteria had an ample amount of nitrite to metabolise;
3. The oft-repeated conventional wisdom suggests that high nitrite concentrations (> 5 ppm) typically result in a stalled cycle.

If I had continued dosing 2 ppm ammonia daily, the prevailing wisdom suggests that I would've required 50% water changes every day given that 1 ppm of ammonia is oxidised to approximately 2.7 ppm nitrite and I would've crossed the threshold of 5 ppm nitrite (2 ppm ammonia = 5.4 ppm nitrite in addition to the pre-existing backlog of nitrite in the aquarium)

To me, it made much more sense to withhold ammonia so that I needn't perform frequent water changes.

You are lacking nitrobacter sufficient enough to change the nitrites into .

If you are still registering nitrites it just means that they have not receive sufficient food to go quickly/almost instantly to nitrates.

Agreed. I mostly posted the data around my nitrite levels as an indication that the cycle is actually progressing, rather than remaining static as it seemed to be a week ago.

 

I am happy to hear that your cycle is now well on its way to complete. The one good thing about all of this is the fact that you should never have to go through it again. Once someone has a fully cycled/established tank when MTS strikes the new tanks can be seeded from the original cycle

 

I should qualify the entirety of my post above with "this is just my opinion based on personal experience".

If other new aquarists read this thread, I can't stress enough that there's so much different and overwhelmingly contradictory information available on cycling aquariums: for every person who says that ammonia oxidising bacteria require daily ammonia doses to stay alive, there's a person who says that they don't; for every person who says that high nitrites will stall a cycle, there's a person who says that they won't; for every person who says that water changes aren't necessary for a fishless cycle, there's a person who says that they are.

I don't have the scientific wherewithal or a background in biology/chemistry to distinguish readily between sound science or myth-turned-conventional-wisdom, so a large part of what I did/am doing is based on a critical reading of what's been posted and what makes sense to me in the context of what's happening in my particular aquarium (and everyone's tank is different!).

With so much information overload at this stage, I'm holding fast in the belief that magical water pixies are converting the ammonia into lollipops to feed the nitrite gremlins.

 

With so much information overload at this stage, I'm holding fast in the belief that magical water pixies are converting the ammonia into lollipops to feed the nitrite gremlins.

I love it ... and now that this theory has been posted it will probably be shared as fact like so many other theory's.

 

I actually had the same thing happen with my 5.5 I just scratch cycled. Ammonia was good within a few days, but the nitrites were building up to insane levels even though the nitrates were doing the same. I started dosing ammonia infrequently, but still no luck. After almost three weeks I finally had enough - drained the tank, refilled it, drained it again, and upon refilling nitrites were still above 1.0! They processed overnight, restarted with the ammonia, and the tank was good to go in four days. All the needed bacteria was there to handle fish, but it was like there was no way it could work through the backlog in the tank. (Meanwhile, the tank next to it was completely done in 6 days.)

 

I actually had the same thing happen with my 5.5 I just scratch cycled. Ammonia was good within a few days, but the nitrites were building up to insane levels even though the nitrates were doing the same. I started dosing ammonia infrequently, but still no luck. After almost three weeks I finally had enough - drained the tank, refilled it, drained it again, and upon refilling nitrites were still above 1.0! They processed overnight, restarted with the ammonia, and the tank was good to go in four days. All the needed bacteria was there to handle fish, but it was like there was no way it could work through the backlog in the tank. (Meanwhile, the tank next to it was completely done in 6 days.)

yep, sometimes it takes a drastic action to get things back in balance.

 

I thought I'd return to this thread and offer a closing update. It's been 3 weeks and one day, and my fishless cycling is complete: 2 ppm ammonia oxidised to nitrite and then to nitrate within 24 hours.

 

I'm jealous. I've been struggling to cycle my tank for almost two months and I just yesterday finally got a very slight trace of nitrites. The process is agonizingly slow but so much less stressful than cycling with fish.

 

I thought I'd return to this thread and offer a closing update. It's been 3 weeks and one day, and my fishless cycling is complete: 2 ppm ammonia oxidised to nitrite and then to nitrate within 24 hours.

Bravo - well done for being patient.
Thankyou for the update.
Enjoy your fish!

 

Enjoy your fish!

Actually, at this stage I'm putting a hold on purchasing fish.

I'm planning to purchase a smaller 10 gallon (which I'll fishless cycle) as a quarantine tank for the first batch of fish (likely a shoal of tetras).

In the mean time, there might be ich in my 47 gallon: I didn't rinse any of my plants/driftwood when I had purchased them, and one LFS had axolotls (which ich can apparently infect) with the anubias. I figure I'll quarantine my display-tank-to-be and wait for any ich to die off.

It would've been better if I had come across this information on day one, but I only did piecemeal research at the start as I didn't want to overload myself with information and experience "paralysis through analysis".

Aside from that, the planted aspect is doing quite well: lots of wisteria, hygro, rotala, anubias, crypts and a foreground of monte carlo carpeting. DIY CO2 and things are definitely growing well. Hopefully it'll be thick and lush in another 2 months when I introduce my first fish!

 

I'm planning to purchase a smaller 10 gallon (which I'll fishless cycle) as a quarantine tank for the first batch of fish (likely a shoal of tetras).

I do that, except I don't keep the tank cycled and full of water all the time. I find that is too much of a hassle.
I keep my quarantine tank in standby dry. When I have a problem or a new fish, I fill it up with tank water form my main tank and move a small filter that I keep "cycled" in the main tank over to the quarantine tank and I'm ready to go!

 

I do that, except I don't keep the tank cycled and full of water all the time. I find that is too much of a hassle.

Agreed! I'm thinking of using a 10-15 gallon for continuous quarantine over several months, adding a new group of fish when the previous group have moved to my planted tank, until my display tank is fully stocked. At that stage, I'll convert it to an invertebrate/shrimp tank.

Then I'll likely buy another 10 gallon (or something smaller, like a 5 gallon) and keep it in storage for quarantine/hospital use.

I'll probably cycle my quarantine tank separately from my current 47 gallon (no use of old tank water or used filter media) as I'm not sure whether ich is present.