The importance of nitrite measurements in a reef aquarium

[MnFish1]

I use a ORP probe and there is few things I can knit to that in the DT tank. But the ORP probe in my anaerobic part of my reversed DSB is the one that manage the control of my denitrification, flow and addition of organic carbon.

IME - the nitrification cycle is one of the most sensitive bacterial processes that happens in a tank and in this - the second step is the most sensitive compared with the first. I use my nitrite measurements in order to monitor the health of my microbial ecosystems and it have give me early warnings a couple of times. One event is a small overdose of organic carbon that makes a shift from nitrifying organism into heterotrophs instead and show up in rising NO2

ORP in open water is not especially useful if you do not use a strong oxidizing agent as O3 or H2O2
The nitrification cycle and its health is much more significant to measure because if the nitrification process will be disturb in a working aquarium - something bad is uprising - IMO

Sincerely Lasse

Curious - I can't remember - do you use an oxydator? Do you see changes in ORP with it (if you do)?

 

[fachatga]

That's a beautiful tank. If I may. To the overall topic. If you're willing to not test nitrite because of its non or low aparent impact. So be it. I'm not intelligent enough for this, however learning is my greatest gift from reefing. I think testing nitrite helps us understand the nitrification process. We should all know how things work. @brandon429 I'd like to say this. I disagree with your delivery (respectfully) I think we should test. And teach others to test for knowledge. What we should be delivering to people is an understanding that it's not a panic situation or a place to need to spend money on useless additives. The nitrification process is the beginning of life in our aquaria. Let's teach that!

I agree wholeheartedly. Whether it’s needed or not if day every new reefer should test to watch the process happen. Maybe I’m a dork but i get a kick out of test results to see things happening like this.

 

[Spieg]

Mt Nitrite levels have tested at or near 0 for so long, I have to admit I only test it a few times a year now.

 

[Lasse]

Mt Nitrite levels have tested at or near 0 for so long, I have to admit I only test it a few times a year now.

I also test rather seldom - around three times a year but I have a baseline and if I run into truble - i test the NO2 concentrations in order to check if there is something that disturb the ecosystem,

Curious - I can't remember - do you use an oxydator? Do you see changes in ORP with it (if you do)?

Yes I do - to both questions

Sincerely Lasse

 

[ReefJonas]

That's a beautiful tank. If I may. To the overall topic. If you're willing to not test nitrite because of its non or low aparent impact. So be it. I'm not intelligent enough for this, however learning is my greatest gift from reefing. I think testing nitrite helps us understand the nitrification process. We should all know how things work. @brandon429 I'd like to say this. I disagree with your delivery (respectfully) I think we should test. And teach others to test for knowledge. What we should be delivering to people is an understanding that it's not a panic situation or a place to need to spend money on useless additives. The nitrification process is the beginning of life in our aquaria. Let's teach that!

Hi, thanks for a good comment. I totally agree. Maybe you misunderstood me. I am on the side that say we should test also for nitrite, as thats an objective indication that the system is mature. So I totally agree with you mate

JOnas

 

[ReefJonas]

Mt Nitrite levels have tested at or near 0 for so long, I have to admit I only test it a few times a year now.

Its ok, but remember, even a nitrite at 0.01 alter the NO3 value by 1 ppm. So, to test NO2 is not just to see if system is mature, but also to get the correct NO3 value. All (I think) NO3 tests works in that way they convert NO3 to NO2, so if you have already some NO2 in tank (and all have) that will give a false high NO3 value if you dont subtract the existing NO2, with a certain factor. There factor is specific for that reagent and method you use, where the factor for FM and TM pro is 100.
ex:
Meaning that if you first measure NO3 only and get 5 mg/l.
In tank we have 0.02 mg/l NO2. That means the true NO3 is: 5-0.02*100= 3 mg/l.
For salifert NO3/NO2 test I think the factor is 25 by the way.

/Jonas

 

[ReefJonas]

Jonas that's a great job, really great job

I assure you that nitrite being positive or negative when you added the very first forms of life to that tank didn't matter, meaning if you added life when ammonia was controlled and never tested for nitrite, the tank would be just as beautiful.
waiting for nitrite control in a cycle didn't earn that great forest, great skill in reefing sure did though.

the most important takeaway to know in relation to those pictures above is that nitrite testing or factoring had zero, zero impact in the outcome.

we are up to page twenty now in my thread of reef tanks starting out who never respond to nitrite. most were nitrite-positive but under full control of ammonia when we starting stocking, their updates are posted.

some are very nice like that one above, see how nitrite is neutral to the end result?

thanks you so much for nice words. I can admit that in this old tank on the pic, I didn’t measure so much at all, more than alkalinity, NO3 and PO4. But there was also a period where I got trouble, and that was in the end where biological load was increased. So I think in a way I finally passed my systems capacity. No issues first 3 years, but then it came more often dino, or cyano. It would have been interesting if I have monitored the system better if I could see an explanation in the parameter, specially nitrogen cycle. I don´t know, but now, as I have my own Mastertronic, I will have better insight. Lets see.

One interesting thing is, I now have increased the load by added some fish and feed heavily, and despite that both PO4, NO3 and NO2 is all extremely low. I take that as an indication that system is mature. I think its not always easy to just see on tank how close you are the upper limit of capacity. Because once you have passed it its too late. AMI the purpose of measure is to detect this limit before you have reached it.

/JOnas

 

[ReefJonas]

Here is my new system, only a 2.5 months old. NO2 is around 0.004 mg/l. NO3 0.5 mg/l, and PO4 0.01 mg/l.-

I have now added 5 fishes and feed heavy and despite that the parameters are same as above, so it seems the system manage the increased load so far.

 

[Ariahsart]

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 NH3/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

It's a good thing I found this, I honestly was worried about it and now understand why I couldn't find much information on this when I was looking for it when I had a spike.

 

[Passgad]

sorry wrong post

 

[Superlightman]

hello, i just did an ICP test yesterday and was surprise to find nitrit in the results, my tank is already a few months olds, should it be a concern??

 

[Randy Holmes-Farley]

hello, i just did an ICP test yesterday and was surprise to find nitrit in the results, my tank is already a few months olds, should it be a concern??

Nope. I do not know if that is accurate or not (it isn't done by ICP), but the level is insignificant in any way except perhaps the interference it causes in some nitrate test kits.

 

[Pod_01]

interference it causes in some nitrate test kits.

Randy are there any nitrate test kits that don’t show interference from nitrite?
I had the impression they all do, but perhaps only hobby test kits are prone to this.

 

[Superlightman]

Nope. I do not know if that is accurate or not (it isn't done by ICP), but the level is insignificant in any way except perhaps the interference it causes in some nitrate test kits.

thanks

 

[Randy Holmes-Farley]

Randy are there any nitrate test kits that don’t show interference from nitrite?
I had the impression they all do, but perhaps only hobby test kits are prone to this.

They can be designed with any multiplier ratio between nitrate and nitrite that the designers want. I’m not sure what they all are and few say. TM says it’s about a factor of 50 and gives a correction table.

The Hanna checker has low interference:

Hanna low range nitrate accuracy, nitrite interference

Is this really true? For the salifert - see this https://en.oceamo.com/post/tröpfchentests-nitrat-nitrit Sincerely Lasse Oceamo did not perform the correct experiment. Their experiment likely does not provide the correct conversion factor and likely exaggerates the nitrite effect, but we...

www.reef2reef.com

At incidental NO2 values (0.1 - 0.2 ppm NO2) that it seems can be found in some established systems, the increase in the measured value of NO3 is not larger than the hanna stated error of +-2ppm or+-5%.

 

[Lasse]

My NO2 concentrations since 2020 - done by OCEAMO that use a special method in order to analyse NO2 - your concentration is normal - IMO

I use the method developed by Hanna with the HI-782 Marine High Range Checker. For the moment with Hanna Marine Master. HI-782 is not very sensitive to NO2. For NO2 - I use HI-764 Hanna Ultra Low Range Nitrite
Below last two years with that checker

Sincerely Lasse

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