The importance of nitrite measurements in a reef aquarium

Lasse

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There have been a lot of threads about nitrification and cycling lately. IMO - the most important measurements tool you have in order to indicate if your cycle is done or not is the nitrite level. It is a rather stable tool and will give stable results with few interferences. One of the myths about nitrite (NO2) is that it should be 0 in a working aquarium. This is not really the truth - it has been shown that concentrations between 0.01 and 0.05 is rather common in reef aquariums. In freshwater aquariums - nitrite is one of the most important tests in use. This is because nitrite in freshwater is rather deadly. Fish take up nitrite from the water through the gills. When nitrite reaches the blood in the fish - it reacts with haemoglobin (the compound responsible for oxygen uptake and transport in the blood) and form methaemoglobin - a substance that is brown and does not bind or transport oxygen. Further on - it has been shown that chlorides in the water will block this uptake of nitrite from the water, hence nitrite is non-toxic for saltwater fish - it will not come into the bloodstream at all.

The acceptance that nitrite is non-toxic in saltwater has led to measurements of nitrite in saltwater to not be as common any longer. However - for me it is one of the more important measurements of different reasons.

Nitrite is formed inside the aquaria from the microbiological processes that always take place and mostly through two major pathways.

Pathway 1

A bad working nitrification process.

The nitrification process consists of two different parts.

The first step is the ammonium oxidation step. This step can be done of many different bacteria strains (AOB) and by different types of archaea (AOA). It starts rather quick and can happen in oxygen levels down to 3 – 4 ppm. It is an important step because it is especially important that total ammonia should not build up into concentrations that allow high levels of the toxic form – ammoniac (ammonia gas or NH3) – in the water. How much of the total ammonia that consist of the toxic form (NH3) is mostly depended on pH, salinity and temperature.
This tool can be a help

The second step is nitrite oxidation into nitrate. This step is done by few bacteria (NOB) – mostly from the genus Nitrobacter and/or from the genus Nitrospira (or Nitrospira like)

This step is more sensitive and often needs oxygen around 5 ppm. It seems also that they need more phosphate in the water in order to have a good growth – and there are some reports that indicate that high ammonia concentration stops this step. The result of a stoppage is that high levels of nitrite will be built up. A nitrite check during the start of the cycle is a good tool that indicate that the cycle is done the whole way. When nitrite levels are down below 0.05 – it is ok – IMO.

Pathway 2a

Pathway 2a is the normal denitrification process. Sooner or later - the denitrification process will start in nearly all aquarium - especially in those with sand beds. This process - in order to be fully completed - demands nitrate, an anaerobic environment and some type of DOC source (external or internal). If this process is not fully worked out – there can be a nitrite build-up.

Pathway 2b

If you use a sulphur-based denitrification – a not fully completed process can result in nitrite build up in the water column if there is not enough filtering capacity for the nitrification pathway.

If nitrite is not toxic in saltwater – why worry?

As I know it – most investigations have been on gill breathing animals with haemoglobin as an oxygen transporter in the bloodstream. There are few other – if any -investigation according animals not using haemoglobin as oxygen carrier and/or in animals that have different oxygen uptake mechanisms than gills. You can´t be sure that there are not animals that take up nitrite in the bloodstream and get into a situation with low uptake of oxygen.

Further on – bacteria and archaea that are important for the nitrification process are oxygen using autotrophs and slow growers. They compete with fast-growing heterotrophs for both oxygen and space to sit on. There is indications that the second step is more sensitive for competition and a build-up of nitrite in a mature system. This can be caused by too much organic load in the system. This is also the reason why we should not add either DOC (dissolved organic carbon) or heterotrophic bacteria in the start of an aquarium. Only nitrifiers should be added in the start. Nitrite measurements in the start cycle show us when the cycle is done, and we can go further with the creation of our unique ecosystem. IMO – this is also the reason why the “rotten shrimp method” should be avoided in the start. If you start with chemical addition of NH
3/NH4 and bottled nitrification bacteria it is essential to know when the nitrite spike is gone IMO. If you start the aquarium the way I have outlined in my 15 steps – you will not have a nitrite spike at all IME.

In a mature aquarium – denitrification will happen. In anaerobic (without oxygen) environment many heterotrophic bacteria can shift from oxygen to nitrate as a metabolic electron acceptor and nitrogen gas will be the waste from that process. This process is named denitrification. However – in this process they need an electron donator too – the denitrification bacteria can use different types of DOC as donators (Dissolved Organic Carbon). If the DOC level is too low – the denitrification process will leak some nitrite and if there is to less nitrification filtering capacity (and – IMO – it is often the case in reef aquarium – some do not want “nitrification factories” – one of the myths – IMO). Nitrite will build up in the water column – a measurement of nitrite will tell us if something happens. It is important to stress that too low DOC concentrations led to nitrite build up by halting the denitrification process and too much DOC led to the inhibition of the nitrification process and further build-up of nitrite in the aquarium. A proper translation of the Swedish word “lagom” would be a good tool here – Lagom means not too much and not too little – maybe – just enough or just right is the proper English expression here.

Nitrite measurements as a tool for proper care of the ecosystem – yes – but can it have other advantages as well?

Many of us measure nitrate as one of the key parameters in our reef. There is a discussion about levels of nitrate. Many uses 5 – 10 as a guideline, other want it to be between 0.5 and 5.

All hobby tests I know (with exception of the upcoming ION director from GHL) are based on the same principle. A metal salt is in use to reduce the nitrate into nitrite. The test reads nitrite but after a certain time when x % of the nitrate has been converted into nitrite. The colour chart translates back the nitrite reading into mg/L nitrate with a certain conversion factor. This factor is depended on brand and metal salt in use but vary from 50 to 100 times. It means that if there is nitrite in the sample from the beginning – you will have a too high reading. The brand I use for the moment (Tropic Marine PRO nitrite/nitrate test. Fauna Marines PRO seems to be the same type) have 100 as a multiplying factor. It means that if I have 0.02 mg/L of nitrite from the beginning – my nitrate readings are 2 mg/L too high. 0.05 ppm nitrite from the beginning -> 5 ppm too high nitrate reading. As I have seen – it is rather normal with these nitrite readings in mature reefs and if I want to have Nitrate levels below 5 mg/L I must analyse my nitrite concentrations in order to get a decent (and right nitrate reading)

IMO even nitrate readings up to 10 mg/L can be very wrong if you do not know your nitrite readings.

As I see it – there are a lot of reasons why nitrite readings should be done both in newly started aquariums and older more mature tanks.

Sincerely Lasse
 
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brandon429

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Nitrite testing in the hobby causes doubt, hesitation, fear over a false condition. reefers buy extra bottle bac and waste money due to this advice. They’re hesitant to clean tanks if it causes a nitrite spike, the advice to react to nitrite presence causes loss of corals.



nobody has accurate nitrite testing they can report

Misread thread examples exist.

api doesn’t just become the most accurate tester avail just because that’s the source of data posts, classic api misreads still apply yet reviews on aquarium nitrite never involve a discussion on test kit misreads and adulterants unstated, such as water prep Prime.



*testing for nitrite and responding to readings is the #2 cause of unneeded bottle bac expenditures in reefing, becase of a conveyed consequence that precious investments will die or be harmed
 
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Lasse

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that nitrite cannot stall a cycle,


That totally true - nitrite in the water will not stall a cycle because it is the result of a stalled cycle. Not the opposite.

Not one cycle in all of reefing has lost a single invertebrate to free nitrite
How do you know that if you do not have monitored the nitrite level?

Sincerely Lasse
 

KrisReef

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Lagom article Lasse.

I decided I would check for the precision of nitrite test kits and Googles gave me nitrate results.

I am going to get a nitrite kit and a new nitrate kit and start tracking results from my tank. I am wondering now if there is something to gain that is reflected in coral growth observations. Nothing scientific except for casual observations presuming that I find useable data motion that correlates to Nitrate-Nitrite measurements.


thanks for the thread,
Sincerely

My tank has been setup for years so I don’t know what to expect really. I presumed zero nitrite and 5 ppm nitrate but without measuring for 10 years I know I don’t really know what the levels are. A couple of test kits can provide a fun distraction from my routine assumptions.
K
 
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Lasse

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nobody has accurate nitrite testing they can report
I do not know how the american nitrite tests work - but the ones I have used from European companies is among the most proven tests that exist.

Sincerely Lasse
 
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Lasse

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I am going to get a nitrite kit and a new nitrate kit and start tracking results from my tank.
I would recommend Fauna Marine or Tropic marines pro tests. They are combined. First you test nitrite with two add ins (A and C). After that you test nitrate the same way but between A and C you add the metal salt (B) - wait for three minutes - after that you ad bottle C. You use the same nitrite test for both tests. I have user Red Seas before but my eyes like the FM test more.

Sincerely Lasse
 

brandon429

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Randys article


doesn’t convey the same urgency as above. I enjoyed reading the first post catching up on metabolic pathways / great read still.


In no way does nitrite factor in a reef cycle, we never miss a single projected start date in my cycle threads that use hundreds of link examples.



post a failed cycle thread you attribute to nitrite
 
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taricha

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I do not know how the american nitrite tests work - but the ones I have used from European companies is among the most proven tests that exist.

Sincerely Lasse
interesting!
I wonder if I can catch nitrite being produced somewhere in my system.

I wonder if it might be easier to catch a small ammonia spike by looking for the nitrite spike? Meaning I wonder which is longer-lived in an established system.

I know Lasse is a hanna skeptic, but
is a reliable nitrite test.
 
Fritz

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Can you be more specific about what you mean by Filtering Capacity?

Pathway 2b

If you use a sulphur-based denitrification – a not fully completed process can result in nitrite build up in the water column if there is not enough filtering capacity for the nitrification pathway.
 

|Tom the Bomb|

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if anyone uses hanna's nitrite checker that tests in ppb it is 100% sure you'll end up with numbers like 7-15 even for me and even hanna show that 7
no wonder ppl in fw like to use a bit of rock salt like api's to help with gills and electrolytes
 

brandon429

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work threads show opposite


cycled, ready, never stalled never factored nitrite. Multiply that by two hundred, its every fish in cycle


he posted in his thread api said 8 ppm. If any reader here claims they wouldnt tell him the cycle stalled, then ur not being truthful. Reported api ammonia at eight ppm scares everyone, always, clockwork.


we then changed water, revealed the functioning bio layer did fine the whole time. This is cycling 2020, can’t stop the deluge

why bother? because knowing what params matter and don’t matter are a function of total reef control, efficiency, and saving money against wasteful expenditures. reefers told him in other threads his cycle that his bacteria were dead now


we stopped a re purchase of bottle bac there using updated cycling science which doesn’t require any testing at all to cycle reef tanks, dry and live rock both. When we need proof though, nh3 control is all that matters.

nitrite levels do not factor in reefing at all. I'm very interested to know what it does in reef cycling and how that matches cycle chart predictions for nitrite control, once we get quality reliable testing shown.
 
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brandon429

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I think nearly all reefers cannot measure nitrite accurately, they wont have Lasse's tester etc
and if told to buy a digital device for it, we need to know why that expenditure was so important.


this thread here didnt say we needed to measure it $$ as a need:
http://reefkeeping.com/issues/2005-06/rhf/index.php

Im not aware of any other sources beyond that to set the pacing regarding nitrite in reefing

Try and locate a single fish-in cycle thread on any forum that didnt work, where the two clowns died




because over ten thousand fish-in cycle threads show successful skipping of cycle, we cannot claim they stalled, or burned fish, or that nitrite mattered. they werent even bothering to factor nh3 in the endeavor lol but bottle bac is that good, nowadays.
 
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Lasse

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Can you be more specific about what you mean by Filtering Capacity?
I was a little bit unclear. It is normally high nitrite levels in the start but can be lowered with lower flow through the filter. After a while you can slowly rise the flow again - without any nitrite release. These sulphur bacteria is autotrophic - it normally means slow growers.

Sincerely Lasse
 
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brandon429

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Lasse can you post any thread where you felt nitrite was impactful, wanted to see the lead up details to that event. accepting any single thread link- the event should be very common based on the rate of speed cycling the world is doing + macna tank entrants over the years / tanks that never stalled out and missed a start date
 
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if anyone uses hanna's nitrite checker that tests in ppb it is 100% sure you'll end up with numbers like 7-15 even for me and even hanna show that 7
no wonder ppl in fw like to use a bit of rock salt like api's to help with gills and electrolytes
There is a company in Austria that have measured nitrite and nitrate levels with scientific equipment for quite a while now. They report nitrite levels between 0 and very high. Normally concentrations is between 0.01 and 0.05. This levels is not dangerous for any life and signal a good working aquarium. However - if you use nitrate measurements and have low concentrations (<5 ppm) they can alter your nitrate readings between 0.5 - 5 ppm depended on the brand you use. Higher nitrite levels indicate something wrong with the microfauna that may need to be take care of. Either a bad working nitrification cycle or a bad working denitrification cycle.

Sincerely Lasse
 

Mortie31

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Good thread, Prof Lasse, you reminded me I hadn’t tested nItrite, since you recommended I test my nitrate reactor to ensure I was getting zero Nitrite. Just tested using salifert and got 0 in tank and 0 in nitrate reactor effluent...
 
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Lasse

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I wonder if it might be easier to catch a small ammonia spike by looking for the nitrite spike?
Most total ammonia tests is not very good - often showing too high levels. Some hobby nitrite tests is very stable and good in both fresh and salt water. I use Hannas fresh water nitrite test every day during a couple of years - analysing fish farm waters. It works like a charm :D I have not tested their saltwater test - but the freshwater works well. A rise in nitrite levels can give a signal that the NH4 is rising too. We did daily tests of how our biofilter works according to ammonia and nitrite oxidation in a testplant I worked at. A rise of NO2 in the outlet was always also followed of a higher amount NH3/NH4 in the outlet too (inlet constant) Not the same percent rise but still a rise.

IMO - the nitrite oxidizers is the most sensitive bacteria group we deal with and a change in their function can give us early warning when thing is going downhill. And only our wish to have the nitrate in certain boundaries give enough of arguments for testing nitrite. IMO - if we want nitrate concentrations below 5 ppm - a nitrite test must also be done in order to not hit zero in nitrate for a prolonged period.

Sincerely Lasse
 
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