Experiencing Unexpected Nitrite Spikes. Please take a read :)

[charlie93]

Hey everyone,

I'm new to the UKAPS community and hoping you can help me (and looking forward to sharing my knowledge too). I've read endless articles/videos/threads so I'll do my best to answer any common questions in the description so you have as much info as possible. I'd really like to diagnose why I'm still getting random Nitrite spikes after a consistent "cycled" phase.

Tank: 40 litre /9 gallon - open top
Light: Twinstar S - 8 hour photoperiod
Filter: Oase Filtosmart Thermo 100 - running at 24 C
Filter Media: Seachem Matrix
CO2: Pressurised. Diffuser line into the tank.
Soil/Substrate: Tropica Soil
Plants: Monte Carlo, S Repens, AR Mini, Rotala Green (Tropica 1-2-grow pots)
Hardscape: 3 Seiryu stones, nothing out of the ordinary
Ferts: Tropica Specialised Nutrition
Livestock: 5 cherry shrimp (added after 8 weeks), 4 otocinclus (added after 9 weeks)
Other: I ensure the lily pipe outflow is slightly above the water to increase surface agitation/oxygen levels

I've been running the tank around 10 weeks now from scratch (filter and media was brand new). Plants have shown great growth and have had a few trims. I did daily 50% water changes for the first week then reduced to every 2nd day in week 2, every 3rd day in week 3 and every 4th day in week 4 and so on... now I've been doing weekly 50% water changes for past few weeks. I've had a diatom bloom and I think I'm at the back end of it now, kept on top of any algae with manual removal as best as I could and the otocinclus have been amazing since adding them to the set up in the past few days. I dose Seachem Prime correctly to tap water before adding to the tank when carrying out a water change. I also added a small dose of Seachem Stability the night before the shrimp were added and the night before the otocinclus were added to encourage additional bacteria growth that may be needed when increasing the bioload from the livestock.

I was really conscious that a new tank may seem "cycled" based on the Ammonia/Nitrite/Nitrate readings so before adding any livestock I ensured I have stable readings for 7 days (Ammonia - 0 ppm /Nitrites - 0 ppm /Nitrates - 30 ppm). I use the API Master Test Kit (expires in 2026).

Since adding the livestock I've had 3 occasions of the Nitrites spiking (2-4 ppm/deep purple). The first came the day after the shrimp were added (I was surprised as I understand they don't have too much bioload). The second came after I cleaned my hoses/lily pipes as they were very brown (I accept that this would cause some change to the bacteria in the system). The other spike was today, I have no idea why... I haven't made any changes to the tank expect 1 25% water change 2 days after the otocinclus were added. I.e. this spike comes 5 days after the otocinclus were added, 3 days after the small water change. I've changed the filter wool once (last week) and of course never cleaned anything to do with filtration/flow in anything other than tank water.

So I ask myself... what is causing the amount of bacteria to drop/die off in the system? Is there enough bacteria in my filter or is there too much in the water column/hardscape/substrate? Is it possible to have too many Nitrates in the water column that stop the Nitrites converting through the cycle?

The Nitrates are there so I definitely have the bacteria but maybe not enough? But I have had enough before and now I don't?

Also, I have baby shrimp. I noticed very small fry about 1 week ago and today I counted around 30+ babies around 3-5mm in length. It makes me think they are happy if they are breeding?

In any case, I've dosed with Prime when noticing the spikes and dosed more Stability to encourage more bacteria colonies. This has helped prevent any of livestock dying but it's not nice seeing them distressed and darting around. I'm now worried about doing any water changes as I fear this could reduce the bacteria again.

The only thing I could think of is that the otocinclus have eaten so much of the diatoms/brown algae and excreted it... maybe this waste is too much for the system to currently process.

Has anyone got any suggestions to what could be the issue here?

Sorry for the lengthy post and any ideas welcome, thank you

Charlie

 

[dw1305]

Hi all,
Welcome to UKAPS, and thank you for your post. I'm pretty sure we can unravel things and the first thing to say is don't panic, I'm confident that there isn't anything seriously amiss.

I'd really like to diagnose why I'm still getting random Nitrite spikes after a consistent "cycled" phase.

It is going to sound a bit of a strange statement but cycling doesn't really exist, and particularly not in terms of <"an on/off switch">.

Since adding the livestock I've had 3 occasions of the Nitrites spiking (2-4 ppm/deep purple). The first came the day after the shrimp were added (I was surprised as I understand they don't have too much bioload). The second came after I cleaned my hoses/lily pipes as they were very brown (I accept that this would cause some change to the bacteria in the system). The other spike was today, I have no idea why... I haven't made any changes to the tank expect 1 25% water change 2 days after the otocinclus were added. I.e. this spike comes 5 days after the otocinclus were added, 3 days after the small water change. I've changed the filter wool once (last week) .....

Pretty much everything you read about nitrification and cycling is wrong. Have a look through <"Test readings not what I expected..."> and the threads linked <"into it">.

Also, I have baby shrimp. I noticed very small fry about 1 week ago and today I counted around 30+ babies around 3-5mm in length. It makes me think they are happy if they are breeding?

This is the important bit, and it tells you the issue lies with the test kits, not the water.

Could we have a full tank shot? It will give us a bit more idea about the level of planting etc.

cheers Darrel

 

[charlie93]

Thanks, Darrel!

Picture attached... Makeshift inlet sponge to protect the baby shrimp.

I must admit, everything I've read about the nitrogen cycle has been contradictory at times. I studied chemical engineering at university so like to think I knew the basics but maybe not 🤣

 

[dw1305]

Hi all,
The tank looks fine and plant growth looks pretty good.

everything I've read about the nitrogen cycle has been contradictory at times. I studied chemical engineering at university so like to think I knew the basics

The issue really is that the <"past is another country">. Once scientists had access to the gene sequences (that coded for ammonia oxidation) they were able to find a huge number of novel organisms, many of them Archaea (AOA), which possessed those genes.

Once scientists started looking at specifically at aquarium filters they found that many of the bacteria, that had been cultured from sewage sludge and required high ammonia loading and carbonate hardness, didn't actually occur and that <"nitrification was carried out by AOA and COMAMMOX Nitrospira spp">. which can directly oxidise ammonia (NH3) to nitrate (NO3).

cheers Darrel

 

[sciencefiction]

Hey Charlie,

Welcome to the forum. I hope you enjoy it as much as all of us have over the years.

I can't comment on what your water conditions are. I just want you to keep in mind that the effect of bad water quality is seen in months. The effect is delayed and not immediate. Fish and water creatures are tough to last a bit in bad water quality and sometimes they tend to give one the perception all is fine until it's too late.
A tank of 40 L is a very small water volume and would be unstable for quite a bit, perhaps the first year while fully maturing.
My best advise is, up the water changes, keep it up for a couple of months or for as long as you can to be on the safe side. Else, in time you will experience weird fish/shrimp diseases or deaths. It's the way it is if one is not up to the game. Fish tanks are enjoyable and laborious at the same time, the first doesn't happen without the second.

 

[charlie93]

Hi all,
The tank looks fine and plant growth looks pretty good.

The issue really is that the <"past is another country">. Once scientists had access to the gene sequences (that coded for ammonia oxidation) they were able to find a huge number of novel organisms, many of them Archaea (AOA), which possessed those genes.

Once scientists started looking at specifically at aquarium filters they found that many of the bacteria, that had been cultured from sewage sludge and required high ammonia loading and carbonate hardness, didn't actually occur and that <"nitrification was carried out by AOA and COMAMMOX Nitrospira spp">. which can directly oxidise ammonia (NH3) to nitrate (NO3).

cheers Darrel

Very interesting! Thanks for sharing

 

[charlie93]

Hey Charlie,

Welcome to the forum. I hope you enjoy it as much as all of us have over the years.

I can't comment on what your water conditions are. I just want you to keep in mind that the effect of bad water quality is seen in months. The effect is delayed and not immediate. Fish and water creatures are tough to last a bit in bad water quality and sometimes they tend to give one the perception all is fine until it's too late.
A tank of 40 L is a very small water volume and would be unstable for quite a bit, perhaps the first year while fully maturing.
My best advise is, up the water changes, keep it up for a couple of months or for as long as you can to be on the safe side. Else, in time you will experience weird fish/shrimp diseases or deaths. It's the way it is if one is not up to the game. Fish tanks are enjoyable and laborious at the same time, the first doesn't happen without the second.

Thanks for your comment, this has put things into more context for me.