Nutrient´s ratio - of importance or not?

[Lasse]

Hi

The goal with this tread is to openly discuss a rather "hot" topic - and maybe state that is time to change "chasing" numbers in favour for chasing ratios.

First some remarks

For me - a compound (read mostly nutrient) is the limited factor for growth if adding it directly will be transferred to more growth of the organism in question. This mean that you can come up to a concentration in the water when adding more - not will result in more growth. Instead something else had become growth limited

I´m not a chemist - I´m not so used of calculating in M and μM - so please correct me if I doing any wrong calculations. Most scientists reports use μM as concentration instead of mg/l. I use the conversion factors - 1 μM PO4 is 0.095 mg/L as PO4 (app 0.095 ppm) - 1 μM NO3 is 0,062 mg/l as NO3 (app 0.062 ppm)

Since the 80:ties - nitrogen have been seen as the limited factor for photosynthetic growth in seawater. Phosphorous (as orto-phosphate) is nearly always present in values around 0.04 mg/l. (around 0.42 μM PO4) Since 2010 - there has been reported some results according to NO3 and bleaching of corals in the wild. The figures mentioned is for us very low (around 0.5 mg/l and lower). For me that want to have a concentration of 2 - 4 ppm NO3 because - IMO - I will not have any serve Cyanobacteria problems with that concentration has it been a problem how to handle this findings. I also know that @Hans-Werner is very careful with NO3 levels.

I recently have a lot of problems with my aquarium - got some cyano, low growth on many types of corals, slowly death of SPS and euphyllia. Since the summer - it looks like it was going downhill - slowly. However - my clams show a good growth and health. In November TRITON ICP test show that my PO4 was lower than 0.018 and the tank was definitely not going well. The reason that it was as low as that was that my new Hanna HI-774 show 0.1 ppm and I try to press it down. The NO3 level was around 4 ppm

I have rise my PO4 level - last Triton show around 0.04 mg/l - and total N around 2.41 mg/l (if all was NO3 - it correspond to 10.65 mg/l NO3) The TRITON DOC test measure all forms of N available for the photosynthesis in aquarium - it means both the inorganic forms - NH3/NH4 and NOX and organic forms like amino acids. In nature - i can´t see any more important source than NO3 because all other forms may only show up locally. For the moment - it all looks very good and the tank improve every day (and it all my corals have improved in growth)

During the last 5 years - there have been some studies according to different ratios between PO4 (the only P source available for photosynthesis) and NO3 (the mos available source in nature)

I have looked into two studies https://www.frontiersin.org/articles/10.3389/fmars.2015.00103/full and https://www.sciencedirect.com/science/article/pii/S0025326X17301601

It is interesting readings because they indicate that a elevated NO3 concentration can make the ZOOX to starve because of Phosphorous limitation (if the PO4 concentration is to low (around 0.02 ppm at NO3 concentrations already around 2 ppm) In an earlier study they saw that at a PO4 concentration of around 0.035 mg/l - a NO3 concentration around 0.4 mg/l was okay. The authors speculate that it could be a threshold value around 0.03 mg/l PO4 - and that is also in line with my experiences.

TRITONS N/P ratio seems to be around 147 N to one P which correspond to a NO3/PO4 ratio of around 100 as mg - it means that if you have 0.04 mg/l PO4 - you could have around 4 mg/l of NO3 if NO3 is the only N source available for photosynthesis. However - that´s not the normal thing in aquarium. In my case - NO3 seems to be around 50 % of my total available N for photosynthesis. My goal - for the moment is around 0.06 - 0.01 mg/l PO4 - which means that I could probably run around 4 ppm as NO3 without any problems. However - I plan to introduce a very effective nitrification filter and probably skim more "wet" in the future - this should make my NO3 concentrations the most important N source for photosynthesis - hence more easy to manage.

Lesson to learn here?

My first is - do not chase PO4 numbers without adjusting the total N available for photosynthesis and do not go down below 0.04 mg/l PO4.

TRITONS N-DOC can be a useful tool

Sincerely Lasse

 

[sixty_reefer]

Thanks for sharing @Lasse hopefully more members will realise that having a low po4 can be a limited factor in photosynthesis.

 

[Randy Holmes-Farley]

I am not a fan of ratios as target levels. If both are independently targeted to proper levels, there is no need to think about ratios.

I don’t deny that off optimal values may cause different types or extents of problems depending on the other, so a ratio has importance, but not as a target.

 

[Dan_P]

Hi

The goal with this tread is to openly discuss a rather "hot" topic - and maybe state that is time to change "chasing" numbers in favour for chasing ratios.

First some remarks

For me - a compound (read mostly nutrient) is the limited factor for growth if adding it directly will be transferred to more growth of the organism in question. This mean that you can come up to a concentration in the water when adding more - not will result in more growth. Instead something else had become growth limited

I´m not a chemist - I´m not so used of calculating in M and μM - so please correct me if I doing any wrong calculations. Most scientists reports use μM as concentration instead of mg/l. I use the conversion factors - 1 μM PO4 is 0.095 mg/L as PO4 (app 0.095 ppm) - 1 μM NO3 is 0,062 mg/l as NO3 (app 0.062 ppm)

Since the 80:ties - nitrogen have been seen as the limited factor for photosynthetic growth in seawater. Phosphorous (as orto-phosphate) is nearly always present in values around 0.04 mg/l. (around 0.42 μM PO4) Since 2010 - there has been reported some results according to NO3 and bleaching of corals in the wild. The figures mentioned is for us very low (around 0.5 mg/l and lower). For me that want to have a concentration of 2 - 4 ppm NO3 because - IMO - I will not have any serve Cyanobacteria problems with that concentration has it been a problem how to handle this findings. I also know that @Hans-Werner is very careful with NO3 levels.

I recently have a lot of problems with my aquarium - got some cyano, low growth on many types of corals, slowly death of SPS and euphyllia. Since the summer - it looks like it was going downhill - slowly. However - my clams show a good growth and health. In November TRITON ICP test show that my PO4 was lower than 0.018 and the tank was definitely not going well. The reason that it was as low as that was that my new Hanna HI-774 show 0.1 ppm and I try to press it down. The NO3 level was around 4 ppm

I have rise my PO4 level - last Triton show around 0.04 mg/l - and total N around 2.41 mg/l (if all was NO3 - it correspond to 10.65 mg/l NO3) The TRITON DOC test measure all forms of N available for the photosynthesis in aquarium - it means both the inorganic forms - NH3/NH4 and NOX and organic forms like amino acids. In nature - i can´t see any more important source than NO3 because all other forms may only show up locally. For the moment - it all looks very good and the tank improve every day (and it all my corals have improved in growth)

During the last 5 years - there have been some studies according to different ratios between PO4 (the only P source available for photosynthesis) and NO3 (the mos available source in nature)

I have looked into two studies https://www.frontiersin.org/articles/10.3389/fmars.2015.00103/full and https://www.sciencedirect.com/science/article/pii/S0025326X17301601

It is interesting readings because they indicate that a elevated NO3 concentration can make the ZOOX to starve because of Phosphorous limitation (if the PO4 concentration is to low (around 0.02 ppm at NO3 concentrations already around 2 ppm) In an earlier study they saw that at a PO4 concentration of around 0.035 mg/l - a NO3 concentration around 0.4 mg/l was okay. The authors speculate that it could be a threshold value around 0.03 mg/l PO4 - and that is also in line with my experiences.

TRITONS N/P ratio seems to be around 70 N to one P which correspond to a NO3/PO4 ratio of around 100 - it means that if you have 0.04 mg/l PO4 - you could have around 4 mg/l of NO3 if NO3 is the only N source available for photosynthesis. However - that´s not the normal thing in aquarium. In my case - NO3 seems to be around 50 % of my total available N for photosynthesis. My goal - for the moment is around 0.06 - 0.01 mg/l PO4 - which means that I could probably run around 4 ppm as NO3 without any problems. However - I plan to introduce a very effective nitrification filter and probably skim more "wet" in the future - this should make my NO3 concentrations the most important N source for photosynthesis - hence more easy to manage.

Lesson to learn here?

My first is - do not chase PO4 numbers without adjusting the total N available for photosynthesis and do not go down below 0.04 mg/l PO4.

TRITONS N-DOC can be a useful tool

Sincerely Lasse

If we try to describe what makes a car thrive, the data suggests a low oil to gasoline ratio is bad. The problem with this way of describing things is that we can have a low oil to gasoline ratio

Hi

The goal with this tread is to openly discuss a rather "hot" topic - and maybe state that is time to change "chasing" numbers in favour for chasing ratios.

First some remarks

For me - a compound (read mostly nutrient) is the limited factor for growth if adding it directly will be transferred to more growth of the organism in question. This mean that you can come up to a concentration in the water when adding more - not will result in more growth. Instead something else had become growth limited

I´m not a chemist - I´m not so used of calculating in M and μM - so please correct me if I doing any wrong calculations. Most scientists reports use μM as concentration instead of mg/l. I use the conversion factors - 1 μM PO4 is 0.095 mg/L as PO4 (app 0.095 ppm) - 1 μM NO3 is 0,062 mg/l as NO3 (app 0.062 ppm)

Since the 80:ties - nitrogen have been seen as the limited factor for photosynthetic growth in seawater. Phosphorous (as orto-phosphate) is nearly always present in values around 0.04 mg/l. (around 0.42 μM PO4) Since 2010 - there has been reported some results according to NO3 and bleaching of corals in the wild. The figures mentioned is for us very low (around 0.5 mg/l and lower). For me that want to have a concentration of 2 - 4 ppm NO3 because - IMO - I will not have any serve Cyanobacteria problems with that concentration has it been a problem how to handle this findings. I also know that @Hans-Werner is very careful with NO3 levels.

I recently have a lot of problems with my aquarium - got some cyano, low growth on many types of corals, slowly death of SPS and euphyllia. Since the summer - it looks like it was going downhill - slowly. However - my clams show a good growth and health. In November TRITON ICP test show that my PO4 was lower than 0.018 and the tank was definitely not going well. The reason that it was as low as that was that my new Hanna HI-774 show 0.1 ppm and I try to press it down. The NO3 level was around 4 ppm

I have rise my PO4 level - last Triton show around 0.04 mg/l - and total N around 2.41 mg/l (if all was NO3 - it correspond to 10.65 mg/l NO3) The TRITON DOC test measure all forms of N available for the photosynthesis in aquarium - it means both the inorganic forms - NH3/NH4 and NOX and organic forms like amino acids. In nature - i can´t see any more important source than NO3 because all other forms may only show up locally. For the moment - it all looks very good and the tank improve every day (and it all my corals have improved in growth)

During the last 5 years - there have been some studies according to different ratios between PO4 (the only P source available for photosynthesis) and NO3 (the mos available source in nature)

I have looked into two studies https://www.frontiersin.org/articles/10.3389/fmars.2015.00103/full and https://www.sciencedirect.com/science/article/pii/S0025326X17301601

It is interesting readings because they indicate that a elevated NO3 concentration can make the ZOOX to starve because of Phosphorous limitation (if the PO4 concentration is to low (around 0.02 ppm at NO3 concentrations already around 2 ppm) In an earlier study they saw that at a PO4 concentration of around 0.035 mg/l - a NO3 concentration around 0.4 mg/l was okay. The authors speculate that it could be a threshold value around 0.03 mg/l PO4 - and that is also in line with my experiences.

TRITONS N/P ratio seems to be around 70 N to one P which correspond to a NO3/PO4 ratio of around 100 - it means that if you have 0.04 mg/l PO4 - you could have around 4 mg/l of NO3 if NO3 is the only N source available for photosynthesis. However - that´s not the normal thing in aquarium. In my case - NO3 seems to be around 50 % of my total available N for photosynthesis. My goal - for the moment is around 0.06 - 0.01 mg/l PO4 - which means that I could probably run around 4 ppm as NO3 without any problems. However - I plan to introduce a very effective nitrification filter and probably skim more "wet" in the future - this should make my NO3 concentrations the most important N source for photosynthesis - hence more easy to manage.

Lesson to learn here?

My first is - do not chase PO4 numbers without adjusting the total N available for photosynthesis and do not go down below 0.04 mg/l PO4.

TRITONS N-DOC can be a useful tool

Sincerely Lasse

Lasse, thanks for the link. It was a fun read.

As for the idea of nutrient ratios, they are useful to process results from multiple variable experiments like this one. It is also good to look at the data without this simplification.

Looking closely at the data, I found that the main conclusion is phosphorous starvation is bad for coral and that many of the responses did not respond differently to low and high nitrogen. This means coral can deal with swings in nitrogen availability much, much better than phosphorous. The potential messages for those growing coral are 1) not to be overly concerned with a stable a nitrogen level, and 2) focus your attention on phosphate level maintenance.

I am also wondering if there is a lesson in here about dinoflagellate nutrition. For example, there is the idea that low nitrate and phosphate are the cause of dinoflagellate flare ups. It might be that very low phosphate is the culprit that causes them to suffer and switch from being photoautotrophs to hetertrophs.

 

[Lasse]

I am not a fan of ratios as target levels. If both are independently targeted to proper levels, there is no need to think about ratios.

I don’t deny that off optimal values may cause different types or extents of problems depending on the other, so a ratio has importance, but not as a target.

I´m not fixed in one ratio either but because of that N seems to be the primary growth limited factor for marine phototropic organisms - a wrong ratio between N and P if P is too low can maybe tip the system into a P limited system instead - and it seems that the coral and its zooxanthellae have problem with that. However in a certain concentrations neither N or P is growth limited and the ratio is not as interesting as before. The authors mention a threshold around 0.03 in PO4 but IMO - the threshold can be higher if light and carbon is not limited.

Yes - @Dan_P I think that the evidences for both cyano mats formation and monoculture of Dinoflagellates are a question of limited inorganic P is increasingly being strengthened.

Sincerely Lasse

 

[YankeeTankee]

I´m not fixed in one ratio either but because of that N seems to be the primary growth limited factor for marine phototropic organisms - a wrong ratio between N and P if P is too low can maybe tip the system into a P limited system instead - and it seems that the coral and its zooxanthellae have problem with that. However in a certain concentrations neither N or P is growth limited and the ratio is not as interesting as before. The authors mention a threshold around 0.03 in PO4 but IMO - the threshold can be higher if light and carbon is not limited.

Yes - @Dan_P I think that the evidences for both cyano mats formation and monoculture of Dinoflagellates are a question of limited inorganic P is increasingly being strengthened.

Sincerely Lasse

Interesting Lasse! Do others here agree there's compelling evidence that a lack of inorganic P may in part cause dinos? I've heard a lack of nutrients in general, but not specifically inorganic P, although I think thats what most at home test kits detect correct? (meaning inorganic and not organic P)

Is there a particular salt of inorganic phosphate you would recommend dosing when P is low?

 

[Randy Holmes-Farley]

Interesting Lasse! Do others here agree there's compelling evidence that a lack of inorganic P may in part cause dinos? I've heard a lack of nutrients in general, but not specifically inorganic P, although I think thats what most at home test kits detect correct? (meaning inorganic and not organic P)

Is there a particular salt of inorganic phosphate you would recommend dosing when P is low?

I do not think there is a likely chance that low P itself directly boosts dinos. That would suggest that, all else unchanged, that increasing P actually slowed the growth of something. I’ve not seen any evidence of that for any organism in the literature within the ranges of concentration we are talking about.

what seems more likely is that low P deters some other organism that is competing with dinos for space or other elements. When the P is raised, that organism thrives and outcompetes dinos. It might just be green algae.

 

[YankeeTankee]

I do not think there is a likely chance that low P itself directly boosts dinos. That would suggest that, all else unchanged, that increasing P actually slowed the growth of something. I’ve not seen any evidence of that for any organism in the literature within the ranges of concentration we are talking about.

what seems more likely is that low P deters some other organism that is competing with dinos for space or other elements. When the P is raised, that organism thrives and outcompetes dinos. It might just be green algae.

Thanks Randy

Either way I'll be dosing phosphate if it drops too low, do you have any preference to a specific type of phosphate salt? Most of the products are inorganic phosphate correct?

 

[Randy Holmes-Farley]

Thanks Randy

Either way I'll be dosing phosphate if it drops too low, do you have any preference to a specific type of phosphate salt? Most of the products are inorganic phosphate correct?

yes, and no preference except for purity grade like food grade.

 

[Scrubber_steve]

Hi

The goal with this tread is to openly discuss a rather "hot" topic - and maybe state that is time to change "chasing" numbers in favour for chasing ratios.

First some remarks

For me - a compound (read mostly nutrient) is the limited factor for growth if adding it directly will be transferred to more growth of the organism in question. This mean that you can come up to a concentration in the water when adding more - not will result in more growth. Instead something else had become growth limited

I´m not a chemist - I´m not so used of calculating in M and μM - so please correct me if I doing any wrong calculations. Most scientists reports use μM as concentration instead of mg/l. I use the conversion factors - 1 μM PO4 is 0.095 mg/L as PO4 (app 0.095 ppm) - 1 μM NO3 is 0,062 mg/l as NO3 (app 0.062 ppm)

Since the 80:ties - nitrogen have been seen as the limited factor for photosynthetic growth in seawater. Phosphorous (as orto-phosphate) is nearly always present in values around 0.04 mg/l. (around 0.42 μM PO4) Since 2010 - there has been reported some results according to NO3 and bleaching of corals in the wild. The figures mentioned is for us very low (around 0.5 mg/l and lower). For me that want to have a concentration of 2 - 4 ppm NO3 because - IMO - I will not have any serve Cyanobacteria problems with that concentration has it been a problem how to handle this findings. I also know that @Hans-Werner is very careful with NO3 levels.

I recently have a lot of problems with my aquarium - got some cyano, low growth on many types of corals, slowly death of SPS and euphyllia. Since the summer - it looks like it was going downhill - slowly. However - my clams show a good growth and health. In November TRITON ICP test show that my PO4 was lower than 0.018 and the tank was definitely not going well. The reason that it was as low as that was that my new Hanna HI-774 show 0.1 ppm and I try to press it down. The NO3 level was around 4 ppm

I have rise my PO4 level - last Triton show around 0.04 mg/l - and total N around 2.41 mg/l (if all was NO3 - it correspond to 10.65 mg/l NO3) The TRITON DOC test measure all forms of N available for the photosynthesis in aquarium - it means both the inorganic forms - NH3/NH4 and NOX and organic forms like amino acids. In nature - i can´t see any more important source than NO3 because all other forms may only show up locally. For the moment - it all looks very good and the tank improve every day (and it all my corals have improved in growth)

During the last 5 years - there have been some studies according to different ratios between PO4 (the only P source available for photosynthesis) and NO3 (the mos available source in nature)

I have looked into two studies https://www.frontiersin.org/articles/10.3389/fmars.2015.00103/full and https://www.sciencedirect.com/science/article/pii/S0025326X17301601

It is interesting readings because they indicate that a elevated NO3 concentration can make the ZOOX to starve because of Phosphorous limitation (if the PO4 concentration is to low (around 0.02 ppm at NO3 concentrations already around 2 ppm) In an earlier study they saw that at a PO4 concentration of around 0.035 mg/l - a NO3 concentration around 0.4 mg/l was okay. The authors speculate that it could be a threshold value around 0.03 mg/l PO4 - and that is also in line with my experiences.

TRITONS N/P ratio seems to be around 70 N to one P which correspond to a NO3/PO4 ratio of around 100 - it means that if you have 0.04 mg/l PO4 - you could have around 4 mg/l of NO3 if NO3 is the only N source available for photosynthesis. However - that´s not the normal thing in aquarium. In my case - NO3 seems to be around 50 % of my total available N for photosynthesis. My goal - for the moment is around 0.06 - 0.01 mg/l PO4 - which means that I could probably run around 4 ppm as NO3 without any problems. However - I plan to introduce a very effective nitrification filter and probably skim more "wet" in the future - this should make my NO3 concentrations the most important N source for photosynthesis - hence more easy to manage.

Lesson to learn here?

My first is - do not chase PO4 numbers without adjusting the total N available for photosynthesis and do not go down below 0.04 mg/l PO4.

TRITONS N-DOC can be a useful tool

Sincerely Lasse

Hi lasse
From what I've read the P/N ratio thing & po4 starvation occurred in the ocean where po4 values were ultra low e.g. 0.008ppm, or something around that. As you said, In lab test they found that once a po4 threshold of 0.028ppm was reached the P/N ratio was less critical. & above this po4 threshold it wasn't important. So if po4 is 0.04ppm or higher one shouldn't be bothering to target a N /P ratio of < 22:1.

Cheers

 

[Big E]

I started to paying attention to ratios around 2005 for my dominant acropora system. When they were at their best in coloration and growth it was approx. 100-1, nitrate to phosphate.

As the years went by I started to document other successful acro tanks and they ranged from 50-200 to 1 with most in that 100-1 range.

Tanks with reverse ranges were never really successful and/or had many algae problems.

As stated very low P04/N03 is an issue with pale corals or limiting factors.

My ball park range for actual numbers is--

Po4-.03-.10ppm
N03- 1.0ppm- 10.0ppm

They are just a general guide I use or suggest as the input of food and the actual throughput of the nutrients is more important.

The amount of fish plays an important role as well as they are the dosers.

As an example, you can have a 100g tank with 3 fish with .05 Po4 and No3 5ppm the tank is doing poorly. That same tank with 6 fish is doing well. The readings are what is left over.

There are also other variables as for example a large algae filter that is consuming a lot of this and out competing the corals especially if the tank is new or just frags starting out.

Also, if you had the same readings above with no fish the tank does poorly, so just adding coral food and getting that same Po4 isn't the same. This goes into the corals taking in ammonium and urea from the fish.

The actual balancing can be done by reducing nutrient control tools or adding fish and food. I like to do things at the front end. Dosing nitrate and phosphate isn't the way to go imo.

Some of this is from helping dozens of reefers and my own anecdotal experiences of 20 years. Whenever the numbers were back in acceptable range and ratio there were always improvements.

Some of this is science, art, math/analytics and personal experience.

There will always be someone to come along an say they run outside the bell curve on the edges but I'm focused on the large number of successes.

In the end the corals never lie so the most valuable tool is visual daily observation and documentation.

I always look at each individual system as well because the export tools, livestock and corals all need consideration along with evaluating the numbers.

 

[Scrubber_steve]

I started to paying attention to ratios around 2005 for my dominant acropora system. When they were at their best in coloration and growth it was approx. 100-1, nitrate to phosphate.

As the years went by I started to document other successful acro tanks and they ranged from 50-200 to 1 with most in that 100-1 range.

Tanks with reverse ranges were never really successful and/or had many algae problems.

As stated very low P04/N03 is an issue with pale corals or limiting factors.

My ball park range for actual numbers is--

Po4-.03-.10ppm
N03- 1.0ppm- 10.0ppm

They are just a general guide I use or suggest as the input of food and the actual throughput of the nutrients is more important.

The amount of fish plays and important role as well as they are the dosers.

As an example you can have a 100g tank with 3 fish with .05 Po4 and No3 5ppm the tank is doing poorly. That same tank with 6 fish is doing well. The readings are what is left over.

There are also other variables as for example a large algae filter that is consuming a lot of this and out competing the corals especially if the tank is new or just frags starting out.

Also, if you had the same readings above with no fish the tank does poorly, so just adding coral food and getting that same Po4 isn't the same. This goes into the corals taking in ammonium and urea from the fish.

The actual balancing can be done by reducing nutrient control tools or adding fish and food. I like to do things at the front end. Dosing nitrate and phosphate isn't the way to go imo.

Some of this is from helping dozens of reefers and my own anecdotal experiences. Whenever the numbers were back in acceptable range and ratio there were always improvements.

Some of this is science, art, math/analytics and most of all for me personal experience.

There will always be someone to come along an say they run outside the bell curve on the edges but I'm focused on the large number of successes.

In the end the corals never lie so the most valuable tool is visual daily observation and documentation.

I always look at each individual system as well because the export tools, livestock and corals all need consideration along with evaluating the numbers.

Great info. Especially as it's derived from aquarium dynamics directly, & not from ocean dynamics (recorded in academia) that may not extrapolate to aquaria. Fish tanks ain't the ocean.

 

[Daniel@R2R]

I feel like I'm not smart enough to dive into this conversation, but I'm enjoying reading and learning.

 

[Zerobytes]

I know I'm not smart enough.

I always have PO4 (.05- .1). Just kind of stays in that range. I can say though that my tank does a lot better with higher NO3 (10-15 ppm). If it gets to 5ppm or less generally cyano and unhappy corals... So I don't shoot for a range directly but I guess indirectly as it seems a higher NO3 in relation to my normal PO4 is best. or it could just be the higher NO3 regardless of the PO4. I offer no help....

 

[Lasse]

I know I'm not smart enough.

I always have PO4 (.05- .1). Just kind of stays in that range. I can say though that my tank does a lot better with higher NO3 (10-15 ppm). If it gets to 5ppm or less generally cyano and unhappy corals... So I don't shoot for a range directly but I guess indirectly as it seems a higher NO3 in relation to my normal PO4 is best. or it could just be the higher NO3 regardless of the PO4. I offer no help....

You are smarter than most of us because you adapt your values after what you see in the aquarium and not after some figures that we haven´t a chance to determine if they are right or wrong. We are trying to measure very low PO4 and NO3 concentrations with hobby tests and according to NO3 - with help of comparing colours. Saltwater is a very complicated solution if you want to test it. There is many ions that can disturb readings and they can differ between tanks (and between time). Most test I have seen does not report the testing method and neither which compounds or ions that can interference with the readings.

i started this thread because - what I have seen - this was the first scientifically reports that mention PO4 starvation as one of the reasons for coral bleaching. It indicate that - below a certain threshold - the ratio of available N and P could have a critical importance because N was not the limited factor and P become it instead (if it was below a threshold figure).

These findings was in line with many peoples experiences in aquarium. However - in the experiment NO3 was the only N source - in aquarium - NO3 is only one of the N species available for photosynthesis. NH3/NH4, NO2 and amino acids are also present and in many cases more than half of all available N.

These articles indicate - as @Big E mentioned - that for most of us - is more safe for our animals that we aim to have figures around 0.05 - 0.1 mg/l as PO4 and 1 - 10 mg/l as NO3 According to PO4 - I have started to advise people to let it go up to around 0.1 - 0.2 if they have problems with coral health and from that - if the corals get better (or when the cyano/problem disappear) slowly working down if they want. In the past - I have been aiming to a NO3 level above 2-3 mg/l as a safe level against Cyano mats formation. I have send in a lot of N-DOC test to Triton and in my case, with this aquarium - my total available N for photosynthesis is 2 - to 2.5 higher. I do not want to go lower than 2 mg/l in NO3 (as I have said in other threads because of other reasons than growth) - therefore I will experiment with faster nitrification and maybe more wet skimming in order to lower the other N sources, Further @AquaBiomics have indicate that successful coral tanks have in general more nitrification bacteria in the water compared with normal tanks

For the book - IMO urea is not produced by saltwater fish (the do not pee of osmotic reasons) - their contribution are mainly NH3/NH4 pumped out through the gills.

In my case - I prefer not to feed very much because I want fishes in natural conditions. I do not either feed with dry food, only with frozen or/and "in house" produced food (read algae and organic detritus). To add - if I get to low left over - and get control over the important throughput (as @Big E stated) - I prefer dosing. With my density of corals, refuge I would need a lot of more detritus eaters in the system. However - I have 40 + fishes in a 320 liters system and feed with 5 - 6 cubes cyclops and - 3 - 4 cubes frozen artemia/mysis each day.

I do not think there is a likely chance that low P itself directly boosts dinos

In general - I´m with you but in this case I think that @Dan_P refer to that some dinoflagellates are capable to swing between autotrophic and heterotrophic feeding and that low availability of inorganic P can be a trigger to change feeding behavior. IMO - it could be a possibility. IMO - the forming of cyano mats also will be triggered by low availability of needed inorganic (including organic amino acids) N and inorganic P in the water column.

Sincerely Lasse

 

[Big E]

Lasse,

On this--

For the book - IMO urea is not produced by saltwater fish (the do not pee of osmotic reasons) - their contribution are mainly NH3/NH4 pumped out through the gills.

To clarify, the urea comes from the gills...........hence NH3/NH4 as you mention.

 

[Dan_P]

You are smarter than most of us because you adapt your values after what you see in the aquarium and not after some figures that we haven´t a chance to determine if they are right or wrong. We are trying to measure very low PO4 and NO3 concentrations with hobby tests and according to NO3 - with help of comparing colours. Saltwater is a very complicated solution if you want to test it. There is many ions that can disturb readings and they can differ between tanks (and between time). Most test I have seen does not report the testing method and neither which compounds or ions that can interference with the readings.

i started this thread because - what I have seen - this was the first scientifically reports that mention PO4 starvation as one of the reasons for coral bleaching. It indicate that - below a certain threshold - the ratio of available N and P could have a critical importance because N was not the limited factor and P become it instead (if it was below a threshold figure).

These findings was in line with many peoples experiences in aquarium. However - in the experiment NO3 was the only N source - in aquarium - NO3 is only one of the N species available for photosynthesis. NH3/NH4, NO2 and amino acids are also present and in many cases more than half of all available N.

These articles indicate - as @Big E mentioned - that for most of us - is more safe for our animals that we aim to have figures around 0.05 - 0.1 mg/l as PO4 and 1 - 10 mg/l as NO3 According to PO4 - I have started to advise people to let it go up to around 0.1 - 0.2 if they have problems with coral health and from that - if the corals get better (or when the cyano/problem disappear) slowly working down if they want. In the past - I have been aiming to a NO3 level above 2-3 mg/l as a safe level against Cyano mats formation. I have send in a lot of N-DOC test to Triton and in my case, with this aquarium - my total available N for photosynthesis is 2 - to 2.5 higher. I do not want to go lower than 2 mg/l in NO3 (as I have said in other threads because of other reasons than growth) - therefore I will experiment with faster nitrification and maybe more wet skimming in order to lower the other N sources, Further @AquaBiomics have indicate that successful coral tanks have in general more nitrification bacteria in the water compared with normal tanks

For the book - IMO urea is not produced by saltwater fish (the do not pee of osmotic reasons) - their contribution are mainly NH3/NH4 pumped out through the gills.

In my case - I prefer not to feed very much because I want fishes in natural conditions. I do not either feed with dry food, only with frozen or/and "in house" produced food (read algae and organic detritus). To add - if I get to low left over - and get control over the important throughput (as @Big E stated) - I prefer dosing. With my density of corals, refuge I would need a lot of more detritus eaters in the system. However - I have 40 + fishes in a 320 liters system and feed with 5 - 6 cubes cyclops and - 3 - 4 cubes frozen artemia/mysis each day.


In general - I´m with you but in this case I think that @Dan_P refer to that some dinoflagellates are capable to swing between autotrophic and heterotrophic feeding and that low availability of inorganic P can be a trigger to change feeding behavior. IMO - it could be a possibility. IMO - the forming of cyano mats also will be triggered by low availability of needed inorganic (including organic amino acids) N and inorganic P in the water column.

Sincerely Lasse

I like the “low PO4 level triggers nuisance organism growth” narrative. It just does not have much support.

The phosphate level of the bulk water does not adequately describe the environment where benthic nuisance organisms grow. This is likely why nuisance organism growth is paradoxical. Phosphate levels in the bulk water are likely to be lower than at the substrate surface or in the pore water. Also, other sources of phosphorous exist that we do not measure and that can be fueling nuisance organism growth. Therefore, a tiny change in the bulk water is unlikely to be noticed by benthic organisms.

Is there even a link between low PO4 level and the proliferation of dinoflagellates and cyanobacteria? I doubt it at this time because very few people who report it can positively identify the nuisance organism, nor have they adequately observed and recorded aquarium conditions to validate the observation that the nuisance organism proliferation happened near the time of PO4 depletion. The case is just not that strong once you remove this information. Mass hysteria might be a better explanation for why we see a connection between low PO4 and nuisance organism growth.

A lack of data and knowledge of the benthic environment in an aquarium means we are making things up to explain benthic nuisance organism growth. And this is not helping us solve the problem. Fortunately, the purported remedies are not harmful and relieve the need we have to “do” something to fight the invasion. I am pretty sure in another 5 years the “low PO4“ narrative will be replaced, possibly, with the “biodiversity” narrative to explain nuisance organism growth.

 

[Gareth elliott]

I use a ratio to start dosing n or p.

but only the ratio of no3/po4 found in macro life waste levels.
So i pick one as a number for its projected effect and add the other in a ratio to that roughly 20n:1p

after a few Days of daily testing adjust to actual usage.

 

[pigmo]

lasse, so many triton users report coral staving no3 po4 levels that we're starting to feel there's some carbon dosing built-in triton core7.

we must dose both no3 and po4 or we go to zeros within 24 hours. both our solutions are autodosed. do a search, there are many recipies for both on this site.

keeping proper po4 levels have been our biggest reefing struggle. much harder than alk... and it goes to zero in our frag tank #2 often. this po4 parameter is so critical for us that it literally controls our alk.

our no3 is stable at 10ppm -- we are currently trying for 0.02 to 0.9ppm po4.


we are waiting for ghl to save us lol... iondirector reserved spot @Vinny@GHLUSA

 

[Nicholas Dushynsky]

I had/ still having issues with low phosphates less than 0.03 on salifert kit. I experienced pale then dying sps and shrinking lps. This caused cyano, then dino which I'm still trying to eradicate, corals still aren't happy but just surviving. This is what my glass looks like after 6 days of not cleaning.im dosing nitrates and phosphates to raise numbers but I don't want go too far the other way. I didnt even test for either until I was slowly losing sps. Now I'm in a horrible game of trying to fix things.