understanding nutrient limitations
1. Introduction
2. Brief description on the difference between Availability and residual nutrients.
3.Identify nutrient limitations under different filtration methods.
3.1. Heterotrophic bacteria as dominant species effect on nutrients and residual.
3.2. Heterotrophic bacteria and autotrophic split dominance effects on nutrient and residual.
4. Influence of other filtration methods and additives on Nutrients
4.1. Filter sock, poly filter and sponges
4.2. Roller mats
4.3. Macro algae’s
4.4. Carbon Dosing
4.5. Phosphates absorbing Medias
4.6. Phosphates artificial dosing
4.7. Nitrates dosing
4.8. Nitrogen dosing
4.9. Protein skimmer
4.10. Water changes
5. Conclusion
1. Introduction
The following article is a update and a more detailed method to understand some of the information that was posted in a previous thread named “the third Nutrient” where I wrote about the importance of the Nutrient C and a few ways to interpret limitations in Reef Aquaria, I have now realised that although the theory is correct it can’t be applied to all systems. This is due to exist two main types of biological filtration in our hobby, one that is mainly done by heterotrophic bacteria, this will be the most common system in the hobby in my opinion, the second type of biological filtration is the split autotrophic and heterotrophic bacteria dominance this will be more common to folks that still have large amounts of live rock or media in a dark Refugium normally in the sump or in the back of a AIO system this kind of filtration promotes nitrifying and denitrifying autotroph to colonise part of the system and may affect the principal nutrient limitation theory.
One of the goals in this article is to aid other members into understanding how to manage nutrient limitations in aquaria.
2. Brief description on the difference between Availability and residual nutrients.
It is important in my opinion to understand the difference between availability of nutrients and residual nutrients to fully understand the information shared through this thread and for a better perception of how nutrients work.
The availability of nutrients it’s the process from the start of decomposition of organic biomass into organic carbon, nitrogen and phosphorus the nutrients will then be slowly release into the water column and be utilised by many different organisms that habitat our systems including coral and macro algae’s.
The most important organism at controlling nutrients will be bacteria, they are the sole responsible organisms to limit Carbon, Nitrogen and depending on each individual biological filtration Phosphorus.
The above nutrients can’t be tested with home grade test kits at present time unfortunately. What we can test is for residual nitrates and phosphates this will be the nutrients that a system is not using hence why they can increase or decrease during nutritional changes to a particular system.
The charts in the pictures below demonstrates the changes in C N P availability in comparison to the expected changes in residual nutrients during carbon dosing. The chart purpose is to illustrate the difference between availability and residual nutrients, on the first picture chart we can observe how a stable tank would look like wend stable and on the second picture chart we can observe that the increase of the availability of organic carbon would made the residual of nitrates and phosphates decrease.
Picture 1
picture 2
3. Identify nutrient limitations under different filtration methods.
3.1. Heterotrophic bacteria as dominant species effect on nutrients and residual.
How I understand the limitations in C N P Availability of nutrients in a system that is mainly biologically filtered by heterotrophic bacteria.
P limits N and C
That may cause N and C to be in abundance
N limits C
That may cause C to be in abundance
How do I understand abundance in C N P availability of nutrients, abundance means if one of the nutrients is in excess
C abundance
May cause N and P be limited
C and N abundance
May cause P to be limited
Knowing the basics of abundance and limitations we may be able to interpret the limitations and abundance of those nutrients using our residual parameters to have a vague idea of what’s happening at the C N P availability of nutrients level.
Residual of phosphates in connection to P
Phosphates decreasing
It may mean P is starting to be less available
Phosphates at zero
It may Mean that P may not be available in the aquarium
Phosphates increasing
It may Mean P is starting to build up in our aquariums
Residual of Nitrates in connection to N
Nitrates decreasing
It may mean N is starting to be less available
Nitrates at Zero
It may mean that N is not available in the aquarium
Nitrates increasing
It may mean N is starting to build up in our aquariums
3.2. Heterotrophic bacteria and autotrophic split dominance effects on nutrient and residual.
How I understand the limitations in C N P Availability of nutrients in a system that is biologically filtered by heterotrophic and autotrophic bacteria.
Residual nitrates going up
It may mean that there’s not enough media supporting denitrification in the sump/display and the display could be limited by the nutrient C
Residual Nitrates going down
It may mean that there is to much media in the sump/display supporting denitrification or a abundance of the nutrient C in the display.
Residual nitrates stable
The balance is just right between display and sump
Residual phosphates going up
It may mean that most of the nutrient N is being processed by Nitrifying autotrophs in the sump or the display is limited By the nutrient N or C.
Residual phosphates going down
It may mean that there is a abundance of the nutrient N and C in the display.
Residual phosphates stable
The balance is just right between display and sump
4. Influence of other filtration methods and additives on Nutrients
4.1. Filter sock, poly filter and sponges
The above filtration can influence the availability of nutrients and residual nutrients, the way they will influence is due to the contact time with the water column the longer it takes in between changes or cleaning the more nutrients will be available to the overall system.
If a system is used to only have them clean or replaced once a week a change in husbandry like moving from weekly to daily could influence the overhaul stability of the supply of available nutrients to a particular system.
4.2. Roller mats
Rollers are definitely a impressive way to automate mechanical filtration the only disadvantage or advantage in my opinion is how effective they are at removing uneaten food from the water column before they start to break down and be able to release nutrients.
If a particular system is observed to start depleting nutrient sometimes by reducing the speed of the roller you should be able to increase the overall availability of nutrients or increase the speed to lower nutrients.
A change from a filter sock to a roller mat could be one of this situations and I would personally recommend that after the change the roller is set to the lower speed for a few weeks to let the organism in the tank adapt to the new availability of nutrients and slowly increase the speed for the previous reasons.
4.3. Macro algae’s
Macro algae’s are a good way to reduce the residual of Nitrates and Phosphates the only thing that makes them a more complex nutrient export is they’re demand in trace elements and sometimes this can become a issue for continuous growth they may also compete with coral for some of the trace elements.
4.4. Carbon Dosing
Carbon dosing in the form of pellets or the many liquid forms it’s a good way to reduce the the build up of the residual nutrients N and P
4.5. Phosphates absorbing Medias
They ideal to adjust the build up of Residual phosphates without making any large changes to the overall balance of the system
4.6. phosphates artificial dosing
It is a efficient way to increase a target nutrient in a controlled fashion.
4.7. Nitrates dosing
It is a efficient way to increase a Target Residual nutrient in a controlled fashion.
4.8. Nitrogen dosing
Nitrogen dosing it is a effective way to increase the availability of N in a system it will also be a good source of nutrients to aid the growth of bacteria population if desired.
4.9. Protein skimmer
They are a effective way to remove excess organics from the water column before they can break down into available nutrients.
4.10. Water changes
In my opinion water changes are not a effective way to control nutrients, they are efficient in emergencies and in other areas of the hobby like replenish trace elements, regarding nutrient control I believe that they are the last resource to look for.
5. Conclusion
The above information is a easier way to interpret what’s happening in a system at the nutrient level, once identified the type of filtration that a system has and the potential dominant bacteria it can becomes easier to understand what is affecting the nutrition on that individual system for a ease of response from the end user to make more informative adjustments if required, I’ve made a effort to keep everything as simple as possible so that folks can understand the methods regardless of the level of experience.
I may have missed a few things although the basics to understand Nutrition will be present in a way or another in the thread.
1. Introduction
2. Brief description on the difference between Availability and residual nutrients.
3.Identify nutrient limitations under different filtration methods.
3.1. Heterotrophic bacteria as dominant species effect on nutrients and residual.
3.2. Heterotrophic bacteria and autotrophic split dominance effects on nutrient and residual.
4. Influence of other filtration methods and additives on Nutrients
4.1. Filter sock, poly filter and sponges
4.2. Roller mats
4.3. Macro algae’s
4.4. Carbon Dosing
4.5. Phosphates absorbing Medias
4.6. Phosphates artificial dosing
4.7. Nitrates dosing
4.8. Nitrogen dosing
4.9. Protein skimmer
4.10. Water changes
5. Conclusion
1. Introduction
The following article is a update and a more detailed method to understand some of the information that was posted in a previous thread named “the third Nutrient” where I wrote about the importance of the Nutrient C and a few ways to interpret limitations in Reef Aquaria, I have now realised that although the theory is correct it can’t be applied to all systems. This is due to exist two main types of biological filtration in our hobby, one that is mainly done by heterotrophic bacteria, this will be the most common system in the hobby in my opinion, the second type of biological filtration is the split autotrophic and heterotrophic bacteria dominance this will be more common to folks that still have large amounts of live rock or media in a dark Refugium normally in the sump or in the back of a AIO system this kind of filtration promotes nitrifying and denitrifying autotroph to colonise part of the system and may affect the principal nutrient limitation theory.
One of the goals in this article is to aid other members into understanding how to manage nutrient limitations in aquaria.
2. Brief description on the difference between Availability and residual nutrients.
It is important in my opinion to understand the difference between availability of nutrients and residual nutrients to fully understand the information shared through this thread and for a better perception of how nutrients work.
The availability of nutrients it’s the process from the start of decomposition of organic biomass into organic carbon, nitrogen and phosphorus the nutrients will then be slowly release into the water column and be utilised by many different organisms that habitat our systems including coral and macro algae’s.
The most important organism at controlling nutrients will be bacteria, they are the sole responsible organisms to limit Carbon, Nitrogen and depending on each individual biological filtration Phosphorus.
The above nutrients can’t be tested with home grade test kits at present time unfortunately. What we can test is for residual nitrates and phosphates this will be the nutrients that a system is not using hence why they can increase or decrease during nutritional changes to a particular system.
The charts in the pictures below demonstrates the changes in C N P availability in comparison to the expected changes in residual nutrients during carbon dosing. The chart purpose is to illustrate the difference between availability and residual nutrients, on the first picture chart we can observe how a stable tank would look like wend stable and on the second picture chart we can observe that the increase of the availability of organic carbon would made the residual of nitrates and phosphates decrease.
Picture 1
picture 2
3. Identify nutrient limitations under different filtration methods.
3.1. Heterotrophic bacteria as dominant species effect on nutrients and residual.
How I understand the limitations in C N P Availability of nutrients in a system that is mainly biologically filtered by heterotrophic bacteria.
P limits N and C
That may cause N and C to be in abundance
N limits C
That may cause C to be in abundance
How do I understand abundance in C N P availability of nutrients, abundance means if one of the nutrients is in excess
C abundance
May cause N and P be limited
C and N abundance
May cause P to be limited
Knowing the basics of abundance and limitations we may be able to interpret the limitations and abundance of those nutrients using our residual parameters to have a vague idea of what’s happening at the C N P availability of nutrients level.
Residual of phosphates in connection to P
Phosphates decreasing
It may mean P is starting to be less available
Phosphates at zero
It may Mean that P may not be available in the aquarium
Phosphates increasing
It may Mean P is starting to build up in our aquariums
Residual of Nitrates in connection to N
Nitrates decreasing
It may mean N is starting to be less available
Nitrates at Zero
It may mean that N is not available in the aquarium
Nitrates increasing
It may mean N is starting to build up in our aquariums
3.2. Heterotrophic bacteria and autotrophic split dominance effects on nutrient and residual.
How I understand the limitations in C N P Availability of nutrients in a system that is biologically filtered by heterotrophic and autotrophic bacteria.
Residual nitrates going up
It may mean that there’s not enough media supporting denitrification in the sump/display and the display could be limited by the nutrient C
Residual Nitrates going down
It may mean that there is to much media in the sump/display supporting denitrification or a abundance of the nutrient C in the display.
Residual nitrates stable
The balance is just right between display and sump
Residual phosphates going up
It may mean that most of the nutrient N is being processed by Nitrifying autotrophs in the sump or the display is limited By the nutrient N or C.
Residual phosphates going down
It may mean that there is a abundance of the nutrient N and C in the display.
Residual phosphates stable
The balance is just right between display and sump
4. Influence of other filtration methods and additives on Nutrients
4.1. Filter sock, poly filter and sponges
The above filtration can influence the availability of nutrients and residual nutrients, the way they will influence is due to the contact time with the water column the longer it takes in between changes or cleaning the more nutrients will be available to the overall system.
If a system is used to only have them clean or replaced once a week a change in husbandry like moving from weekly to daily could influence the overhaul stability of the supply of available nutrients to a particular system.
4.2. Roller mats
Rollers are definitely a impressive way to automate mechanical filtration the only disadvantage or advantage in my opinion is how effective they are at removing uneaten food from the water column before they start to break down and be able to release nutrients.
If a particular system is observed to start depleting nutrient sometimes by reducing the speed of the roller you should be able to increase the overall availability of nutrients or increase the speed to lower nutrients.
A change from a filter sock to a roller mat could be one of this situations and I would personally recommend that after the change the roller is set to the lower speed for a few weeks to let the organism in the tank adapt to the new availability of nutrients and slowly increase the speed for the previous reasons.
4.3. Macro algae’s
Macro algae’s are a good way to reduce the residual of Nitrates and Phosphates the only thing that makes them a more complex nutrient export is they’re demand in trace elements and sometimes this can become a issue for continuous growth they may also compete with coral for some of the trace elements.
4.4. Carbon Dosing
Carbon dosing in the form of pellets or the many liquid forms it’s a good way to reduce the the build up of the residual nutrients N and P
4.5. Phosphates absorbing Medias
They ideal to adjust the build up of Residual phosphates without making any large changes to the overall balance of the system
4.6. phosphates artificial dosing
It is a efficient way to increase a target nutrient in a controlled fashion.
4.7. Nitrates dosing
It is a efficient way to increase a Target Residual nutrient in a controlled fashion.
4.8. Nitrogen dosing
Nitrogen dosing it is a effective way to increase the availability of N in a system it will also be a good source of nutrients to aid the growth of bacteria population if desired.
4.9. Protein skimmer
They are a effective way to remove excess organics from the water column before they can break down into available nutrients.
4.10. Water changes
In my opinion water changes are not a effective way to control nutrients, they are efficient in emergencies and in other areas of the hobby like replenish trace elements, regarding nutrient control I believe that they are the last resource to look for.
5. Conclusion
The above information is a easier way to interpret what’s happening in a system at the nutrient level, once identified the type of filtration that a system has and the potential dominant bacteria it can becomes easier to understand what is affecting the nutrition on that individual system for a ease of response from the end user to make more informative adjustments if required, I’ve made a effort to keep everything as simple as possible so that folks can understand the methods regardless of the level of experience.
I may have missed a few things although the basics to understand Nutrition will be present in a way or another in the thread.
I also find the way that it is written fairly average for the section were this article is positioned (General Reefing), it is very disappointing that both reviews on this article seem more of a personal issues with the author instead of being rated on the actual content of the article, both members commented on the discussion thread to post they’re feeling although none seemed to ask any questions regarding the nature of the reviews.
Thanks