Why is there a nutrient imbalance?

[JayPat852]

Hi all,

Last week I posted about my NO3:PO4 ratio (initially 2.5 ppm NO3, 0.1 ppm PO4). Then two of my four Goni frags started declining. Tested NO3 and it plummeted to 0.2 ppm while PO4 remained at 0.1 ppm. Following advice from previous post, I increased feeding and added a small dose of AF Manganese (1/5 recommended), which initially improved the Goni's. I also halved my refugium photoperiod to 5 hours, hoping to boost NO3.

However, a few days later my tests showed PO4 rising to 0.2 ppm and NO3 dropping to 0. I then switched from Mysis to increased seaweed feeding, aiming to lower PO4 and raise NO3.

Currently, my parameters fluctuate daily: NO3 hovers around 0 ppm in the morning and 0.2 ppm in the evening, while PO4 is around 0.1 ppm in the morning and 0.2 ppm in the evening (likely due to the refugium's influence). All other corals are thriving, but the two Goni's have retracted again.

Tomorrow, I'll be starting to dose nitrates and return to my original feeding schedule. With the goal is to raise NO3 through dosing while hopefully returning PO4 to 0.1 ppm through going back to my old feeding regiment. If PO4 remains elevated, I'll begin using GFO.

My main questions are:

- Why are my nitrates remaining so low, even with increased feeding and changing to a more algae based food source and a reduced nutrient export (1/2 refugium photoperiod)?

- Regarding refugium's, from my understanding chaeto (what I'm using) consumes more NO3 than PO4, Are there any other macros that consume a more balanced ratio of NO3:PO4 (I could be completely wrong but its what I've been told but haven't read up about it).
-If there is a macro that use a more balanced ratio, why is there difference in nutrient consumption of nutrients in macros? Is it colour? I understand the difference between softies, LPS and SPS consumption. But Macros i'd like to learn more about.

-What biological process is causing this rapid nitrate reduction while phosphates remain relatively stable even with the reduction of skim and photoperiod? After some reading, is it due to anerobic areas in the tank which?

I generally understand the solutions to nutrient imbalances through additions of chemicals like gfo and adding nitrates etc, but I'm struggling to understand why these changes are happening and how to change these naturally as. It feels like we often discuss the "what's wrong" and "how to fix" in this hobby, but not the "why."

Sorry for the very long winded post and hope it all it makes sense. If you need any more info on my tank let me know and I greatly appreciate any input!


FYI All corals are doing great apart from those 2 Goni's .
All of my other parameters are stable:
-Temp 27C
- Salinity 1.025
- Kh 9.5
- Ca 400
- Mg 1300.

 

[Randy Holmes-Farley]

I'd give up focusing on the way it arose as there are many processes in reef tanks that add or remove only one of N and P, and just look at dealing with it. The situation does not imply any sort of problem with the various processes taking place.

IMO, your best choices are to feed more and accept a bit higher phosphate, which is likely fine.

Or dose some sort of N supplement, preferably ammonium bicarbonate, to ensure there is adequate N for corals.

 

[JayPat852]

I'd give up focusing on the way it arose as there are many processes in reef tanks that add or remove only one of N and P, and just look at dealing with it. The situation does not imply any sort of problem with the various processes taking place.

IMO, your best choices are to feed more and accept a bit higher phosphate, which is likely fine.

Or dose some sort of N supplement, preferably ammonium bicarbonate, to ensure there is adequate N for corals.

Thanks for the advice.

I understand that most people just want to focus on how to fix the issue at hand and appreciate that you think i shouldn't look at the way it arose. But I've always been a person that wants to understand why stuff happens. rather than just how to fix it to deeper my understanding. I took a 3 year break from the hobby so have had to many questions building up. Gonna go do some digging in articles and see if i can find out any more info. Very nerdy of me I know haha.

 

[Randy Holmes-Farley]

Thanks for the advice.

I understand that most people just want to focus on how to fix the issue at hand and appreciate that you think i shouldn't look at the way it arose. But I've always been a person that wants to understand why stuff happens. rather than just how to fix it to deeper my understanding. I took a 3 year break from the hobby so have had to many questions building up. Gonna go do some digging in articles and see if i can find out any more info. Very nerdy of me I know haha.

No need to dig around, I can provide the many ways that nutrients do not always move together.

1. Denitrification as a process uses nitrate and not phosphate

2. The N/P ratio is not the same in all foods. Some are known as high P (Reef Roids), others have lower P. Much of the time we do not know the ratio in foods we use.

3. Phosphate binds to any exposed calcium carbonate surface, and the amount bound depends on the concentration in the water. That adds phosphate when you try to lower it, and takes up phosphate when you try to raise it.

4. Some rock comes with phosphate already on it.

5. RO/DI water can contain some phosphate.

6. Not all organisms use the same ratio of N to P. Even among seemingly similar organisms, such as macroalgae, the ratio varies.

7. Freshly deposited coral skeletons will bind phosphate but not nitrate.

8. Cyanobacteria can get N from the N2 in the air, and thus can add N into the system when they die.

I'm sure there are more, but these are what come immediately to mind.

 

[JayPat852]

No need to dig around, I can provide the many ways that nutrients do not always move together.

1. Denitrification as a process uses nitrate and not phosphate

2. The N/P ratio is not the same in all foods. Some are known as high P (Reef Roids), others have lower P. Much of the time we do not know the ratio in foods we use.

3. Phosphate binds to any exposed calcium carbonate surface, and the amount bound depends on the concentration in the water. That adds phosphate when you try to lower it, and takes up phosphate when you try to raise it.

4. Some rock comes with phosphate already on it.

5. RO/DI water can contain some phosphate.

6. Not all organisms use the same ratio of N to P. Even among seemingly similar organisms, such as macroalgae, the ratio varies.

7. Freshly deposited coral skeletons will bind phosphate but not nitrate.

8. Cyanobacteria can get N from the N2 in the air, and thus can add N into the system when they die.

I'm sure there are more, but these are what come immediately to mind.

Thank you very much for this response, definitely covers a lot of my queries.

Got a few questions though if you'd let me pick you mind :) :

'2. The N/P ratio is not the same in all foods. Some are known as high P (Reef Roids), others have lower P. Much of the time we do not know the ratio in foods we use.'
- If we know that certain foods have increased or lower p, is this because they have increased protein based products uses in the food rather than algae based? Secondly, if this fact is well known, why do companies not promote that they are lower PO4 or NO3 etc?

'4. Some rock comes with phosphate already on it.' -
In what form is it stored? what other elements are stored?
In nature, is there any benefits of storing PO4? first thing that comes to mind is primary succession

'6. Not all organisms use the same ratio of N to P. Even among seemingly similar organisms, such as macroalgae, the ratio varies.'
- Complete theory on my end, but would i be right in saying that corals with a higher surface area i.e euphillya would require more nitrates than other due to the increases surface area of zooxanthellae which uses nitrogen

I know I'm sounding really nerdy but hopefully any responses can help other people understand about why out tanks work the way they do.

 

[Pod_01]

It feels like we often discuss the "what's wrong" and "how to fix" in this hobby, but not the "why."

The “why” your NO3 is low is likely due to this:

Regarding refugium's, from my understanding chaeto (what I'm using) consumes more NO3 than PO4,

Also I suspect the following:

I increased feeding and added a small dose of AF Manganese (1/5 recommended), which initially improved the Goni's.

Helped feed your cheato… and used up NO3.

One question to ask yourself, am I trying to grow corals or am I trying to grow cheato?

If cheato is growing well and corals are not, perhaps your issue to address is this imbalance.

Just my opinion, I don’t have fuge and my focus is to grow corals:

I use skimmer and some GAC…
Fuge can make things complicated from my experience, the reef will self regulate algae growth…

Good luck,

 

[JayPat852]

The “why” your NO3 is low is likely due to this:



Also I suspect the following:

Helped feed your cheato… and used up NO3.

One question to ask yourself, am I trying to grow corals or am I trying to grow cheato?

If cheato is growing well and corals are not, perhaps your issue to address is this imbalance.

Just my opinion, I don’t have fuge and my focus is to grow corals:

I use skimmer and some GAC…
Fuge can make things complicated from my experience, the reef will self regulate algae growth…

Good luck,

Cheers for the response!

I don't focus on what my Chaeto is doing. My corals are doing really well and have full polyp extension apart from two of my gonis. The advice that was given in my previous thread was to increase my nutrients to help them out however as stated I've had little luck.

The purpose of starting this new thread was to try an understand more about the science regarding low nutirents in reef tanks rather than the solution / way to fix it.

 

[Randy Holmes-Farley]

Thank you very much for this response, definitely covers a lot of my queries.

Got a few questions though if you'd let me pick you mind :) :

'2. The N/P ratio is not the same in all foods. Some are known as high P (Reef Roids), others have lower P. Much of the time we do not know the ratio in foods we use.'
- If we know that certain foods have increased or lower p, is this because they have increased protein based products uses in the food rather than algae based? Secondly, if this fact is well known, why do companies not promote that they are lower PO4 or NO3 etc?

It is well known that some foods naturally contain more phosphate than others. Phosphate is present in all natural foods, but not at the same N/P ratios. Some food companies, such as benepets, claim to intentionally make a lower p food. You can see from the list linked for seafoods that phosphate does not necessarily track with protein:

Shellfish

Shellfish like crab, lobster, and shrimp are rich in protein, iron, and omega-3s. They’re low in calories but high in cholesterol. Safe to eat with kidney disease; check with your dietitian.

www.kidney.org

'4. Some rock comes with phosphate already on it.' -
In what form is it stored? what other elements are stored?
In nature, is there any benefits of storing PO4? first thing that comes to mind is primary succession

The primary issue may be be that some types of calcium carbonate get exposed to phosphate in the environment and phosphate binds to the rock surfaces. It can then be released into the water. Used rock from another tank can do the same thing.

Phosphate binding to rock and sand serves to buffer the phosphate concentration, slowing any rise or fall. Whether that is an advantage or disadvantage depends on what you are trying to do.

'6. Not all organisms use the same ratio of N to P. Even among seemingly similar organisms, such as macroalgae, the ratio varies.'
- Complete theory on my end, but would i be right in saying that corals with a higher surface area i.e euphillya would require more nitrates than other due to the increases surface area of zooxanthellae which uses nitrogen

I'm not aware of any reason to think surface area has a relationship to the internal N and P ratio of an organism. Both are used for a very wide range of biomolecules, and exactly what sets of biomolecules make up an individual organism will determine the amount of each.

 

[BryanM]

If it helps my current Nitrate 23, Phosphate .33, and my tank has never looked better right now.

Unless one is striving for an ultra low nutrient system I wouldn't worry about your phosphate and I'd simply try and raise your nitrates.

 

[JayPat852]

Hi all,
Just thought I'd provide a small update.
Started dosing nitrates and have maintained a 5 hour photoperiod for my refugium and could definitely see the Goni 'inflate' more the following day but still not fully open. However, on one of the sides of the goni i noticed some 'algae' growing on it, however due to my low nutrients i don't have much anywhere else in the tank.

Just now i decided to do an iodine dip so hopefully i see some improvement. my justification for the iodine dip was because in my old tank i had a goniastrea which presented with the same algae like appearance on it and did an iodine dip. 2 days later it was gone making me think its a bacterial infection. Im not sure of the history of this Goni as to whether its wild or aqua cultured as i don't speak Cantonese (I live in Hong Kong, google translate can only get me so far :grinning-face-with-smiling-eyes:).

Even if it isn't an bacterial infection, just curious if there is a way to prevent bacterial infections from entering the tank, what dip would be most affective against this apart from iodine based antibiotics? currently using redsea dip which is more herbal extract base which i dont believe has much antibiotic properties. i could be wrong but would love any input

 

[Randy Holmes-Farley]

Even if it isn't an bacterial infection, just curious if there is a way to prevent bacterial infections from entering the tank, what dip would be most affective against this apart from iodine based antibiotics? currently using redsea dip which is more herbal extract base which i dont believe has much antibiotic properties. i could be wrong but would love any input

I'll have to leave the dip questions to others as I've never dipped a coral and have not examined the choices well.

 

[JayPat852]

I'll have to leave the dip questions to others as I've never dipped a coral and have not examined the choices well.

Ok thanks Randy.

On a side note, after looking into some articles on my lunch break i found these two regarding coral surface area and growth from a mathematical approach. In addition, another interesting read about NO3 and PO4. They are both fairly long but both go into heaps of detail

 

[Randy Holmes-Farley]

Thanks. :)

The main point of the second one is something I reiterated in my recent article: that what corals one is using and what endpoints one is using can impact what the effects of various N and P levels are.

Impact of nitrogen (N) and phosphorus (P) enrichment and skewed N:P stoichiometry on the skeletal formation and microstructure of symbiotic reef corals - Coral Reefs

Reported divergent responses of coral growth and skeletal microstructure to the nutrient environment complicate knowledge-based management of water quality in coral reefs. By re-evaluating published results considering the taxonomy of the studied corals and the N:P stoichiometry of their...

link.springer.com

Reported divergent responses of coral growth and skeletal microstructure to the nutrient environment complicate knowledge-based management of water quality in coral reefs. By re-evaluating published results considering the taxonomy of the studied corals and the N:p stoichiometry of their nutrient environment, we could resolve some of the major apparent contradictions. Our analysis suggests that Acroporids behave differently to several other common genera and show distinct responses to specific nutrient treatments.

Randy’s Thoughts on Nutrient Target Ranges

Thoughts on Nutrient Target Ranges by Randy Holmes-Farley Almost nothing in the world of reef aquarium chemistry causes as much discussion as selecting and maintaining ranges for nitrate and phosphate. Some aquarists want low targets, some want...

www.reef2reef.com

In addition to different organisms being used by different aquarists to assess what is best in nutrient terms, there are many different endpoints that one reefer may focus on that are different from another reefer, even assessing the same coral and its local environment. Some of these are:
Polyp expansion
Growth rate
Color
Pest algae
Pest dinoflagellates
Pest cyanobacteria
Pest diatoms
Others

 

[JayPat852]

Thanks. :)

The main point of the second one is something I reiterated in my recent article: that what corals one is using and what endpoints one is using can impact what the effects of various N and P levels are.

Impact of nitrogen (N) and phosphorus (P) enrichment and skewed N:P stoichiometry on the skeletal formation and microstructure of symbiotic reef corals - Coral Reefs

Reported divergent responses of coral growth and skeletal microstructure to the nutrient environment complicate knowledge-based management of water quality in coral reefs. By re-evaluating published results considering the taxonomy of the studied corals and the N:P stoichiometry of their...

link.springer.com

Reported divergent responses of coral growth and skeletal microstructure to the nutrient environment complicate knowledge-based management of water quality in coral reefs. By re-evaluating published results considering the taxonomy of the studied corals and the N:p stoichiometry of their nutrient environment, we could resolve some of the major apparent contradictions. Our analysis suggests that Acroporids behave differently to several other common genera and show distinct responses to specific nutrient treatments.

Randy’s Thoughts on Nutrient Target Ranges

Thoughts on Nutrient Target Ranges by Randy Holmes-Farley Almost nothing in the world of reef aquarium chemistry causes as much discussion as selecting and maintaining ranges for nitrate and phosphate. Some aquarists want low targets, some want...

www.reef2reef.com

In addition to different organisms being used by different aquarists to assess what is best in nutrient terms, there are many different endpoints that one reefer may focus on that are different from another reefer, even assessing the same coral and its local environment. Some of these are:
Polyp expansion
Growth rate
Color
Pest algae
Pest dinoflagellates
Pest cyanobacteria
Pest diatoms
Others

Thank Randy I'll give your article a deeper read!

Just skimmed through your article and it covers all of the questions i have, thank you for providing this. However after reading some of the articles provided I've got a few questions. firstly, The study i listed above classified high PO4 at like 0.037ppm. I noticed that you mentioned to start dosing if below 0.06, but if research is showing that 0.037 is the best should we not aim for that, and is there more research on higher level PO4 that I've missed. in addition, why is it than in the reefing hobby you could have someone with a ULNS and also someone with significantly elevated nutrients with coral growth nearly identical when articles show different results. does it have to do with most of the corals found in our hobby being aquacultured and adapted to higher nutrients.

secondly, most articles say that nitrates decrease overall coral growth but phosphates have limited or even improve coral growth. To this point, should reefers be less focussed on po4 and more focused on NO3 as the elevated NO3 is what can resulted in the decreased PO4 due to alagae which then has detrimental effects on the coral. meaning nitrates are the catalyst for negative effects and PO4 is just an accessory and doesnt dirrectly affect coral and is only when NO3 is elevated that is when an issue arises

 

[Randy Holmes-Farley]

Thank Randy I'll give your article a deeper read!

Just skimmed through your article and it covers all of the questions i have, thank you for providing this. However after reading some of the articles provided I've got a few questions. firstly, The study i listed above classified high PO4 at like 0.037ppm. I noticed that you mentioned to start dosing if below 0.06, but if research is showing that 0.037 is the best should we not aim for that, and is there more research on higher level PO4 that I've missed. in addition, why is it than in the reefing hobby you could have someone with a ULNS and also someone with significantly elevated nutrients with coral growth nearly identical when articles show different results. does it have to do with most of the corals found in our hobby being aquacultured and adapted to higher nutrients.

secondly, most articles say that nitrates decrease overall coral growth but phosphates have limited or even improve coral growth. To this point, should reefers be less focussed on po4 and more focused on NO3 as the elevated NO3 is what can resulted in the decreased PO4 due to alagae which then has detrimental effects on the coral. meaning nitrates are the catalyst for negative effects and PO4 is just an accessory and doesnt dirrectly affect coral and is only when NO3 is elevated that is when an issue arises

There are all sorts of different types of info that went into my recommendations, and in general, I weighted reef tank user experiences more than published science studies which are often short term and in situations that do not reflect the realities of reef tanks. IMO, the published studies are way more useful for understanding mechanisms and such rather than what would be good target levels for nutrients in a typical reef tank.

The recommendations also need to reflect the realities of hobby testing. Since I am of the opinion that total N and P levels too low are considerably worse than levels too high, that tells me to bring up the bottom end of the recommended range since someone right at the bottom might actually be well below it.

I note in the article that ULNS systems (such as zeovit) provide other sources and N and P than nitrate and phosphate (such as whole bacteria). That is very important, IMO.

 

[JayPat852]

There are all sorts of different types of info that went into my recommendations, and in general, I weighted reef tank user experiences more than published science studies which are often short term and in situations that do not reflect the realities of reef tanks. IMO, the published studies are way more useful for understanding mechanisms and such rather than what would be good target levels for nutrients in a typical reef tank.

The recommendations also need to reflect the realities of hobby testing. Since I am of the opinion that total N and P levels too low are considerably worse than levels too high, that tells me to bring up the bottom end of the recommended range since someone right at the bottom might actually be well below it.

I note in the article that ULNS systems (such as zeovit) provide other sources and N and P than nitrate and phosphate (such as whole bacteria). That is very important, IMO.

Thanks Randy! really appreciate the clarification on your in depth research into the topic.

My background is in the healthcare sector in which we have the general medical research which has loads of clinical studies supporting it in addition to social prescribing which has much fewer research but from a community basis has shown great results.

Its people like you Randy who cross the bridge between the scientifc research (medical research) and reefing community based observations (social prescribing) that help me and others develop a greater understanding of our tanks and i greatly appreciate it. As most of the information online regarding reefing are observational without the evidence to back it.

From a quick skim online it looks like there is very few articles about the link between scientists and hobbyists but they are all qualitative studies. would love to see a direct comparison / literature review with comparative date in how the parameters we get in our tank differ to the ones found in most of the articles. as previously stated, the "high nutrients" are lower that what most see in their tank.

Really appreciate your input into this topic

 

[Randy Holmes-Farley]

previously stated, the "high nutrients" are lower that what most see in their tank.

Really appreciate your input into this topic

Thanks.

Scientists studying elevated nutrients will generally look at situations that might arise in the ocean. The ocean never gets to 50 ppm nitrate and 1 ppm phosphate, so the incentive to spend time studying it is almost entirely limited to the hobby.

 

[JayPat852]

Thanks.

Scientists studying elevated nutrients will generally look at situations that might arise in the ocean. The ocean never gets to 50 ppm nitrate and 1 ppm phosphate, so the incentive to spend time studying it is almost entirely limited to the hobby.

Would love to see more information passed from the hobby over to research. However, as you previously mentioned, hobby grade testing just has too much variability and lack of specificity. Do you think maybe ICP test companies could share information regarding reef tank results? Alternatively, do you think it would benefit research if reefers who have done an ICP tests sent their results etc to marine research companies. Or are their just too many factors at hand?

 

[Randy Holmes-Farley]

Would love to see more information passed from the hobby over to research. However, as you previously mentioned, hobby grade testing just has too much variability and lack of specificity. Do you think maybe ICP test companies could share information regarding reef tank results? Alternatively, do you think it would benefit research if reefers who have done an ICP tests sent their results etc to marine research companies. Or are their just too many factors at hand?

I think one would need to identify a problem that scientists were interested in studying that reefs could help with. I don't think many would be interested in, say, what level of manganese made a certain coral more colorful or grow faster.

 

[JayPat852]

With regards to your example about manganese.. there are a few studies about the influence of manganese on stress of corals but all are with significant reference to global warming. Going off on a tangent, but i suppose like with most things, political topics influence where resource are allocated for research. That being said the new docuseries 'our ocean' narrated by Obama and the regular media update from the ocean cleanup project will hopefully increase visibility to the topic and push more resources for future research on other areas of reefing chemistry. And the second point from what you said about 'growing faster', would that not interest scientists with the rapid reduction of reefs globally which again is a well covered political topic? I just think that with all the knowledge hobbyist and coral farmers have to increase coral growth and maximise efficiency that it would be incredibly useful for future research and development (yes its on a larger scale but you get what i mean)
-I've seriously deviated from the original topic off this thread but would love to understand someone with your experience opinion