Could we utilise the Redfield ratio a little better in aquaria?

[sixty_reefer]

Is it possible the desire to scrub all detritus via skimmer or sock or roller mat might be causing the limitations vs letting natural decomposition thereby ensuring there's always an influx of nutrients considering we really don't know what causes an imbalance and resulting phosphates and nitrates solved via carbon dosing and GFO/LC as well as natural solutions such as algae and/or sponges?

Keeping a box of water and rocks is far removed from what is naturally occurring on an actual reef and perhaps trying to mimic that better than this craze with trying be Mr Clean.

They all different variables and options available to keep a reef tank stable, they all correct in their own way. Me personally i would be adding macro algaes to my environment if I was looking at growing corals that need an absolute balance and stability due to their impact on nutrient fluctuations making more difficult to keep a system stable long term not to mention the direct competition with coral.

 

[BeanAnimal]

This has to be one of the most pseudo-intellectual and artificially pedantic reefing "conversations" I think I have ever seen. We are 9 pages in and I don't think anybody has any idea (we are low IQ I suppose) what the actual point is.

 

[GARRIGA]

They all different variables and options available to keep a reef tank stable, they all correct in their own way. Me personally i would be adding macro algaes to my environment if I was looking at growing corals that need an absolute balance and stability due to their impact on nutrient fluctuations making more difficult to keep a system stable long term not to mention the direct competition with coral.

Fish produce ammonia which the corals have first shot at then scrubbed by the algae and any elements they utilize such as iron can be replenished as needed. How it is in nature.

I don't subscribe to this theory nitrates and phosphates must be maintained within a narrow range being that's not what occurs in nature. Why I mention the need to change this mantra of trying to sterilize the tank by pulling out that which needs to decompose naturally.

My approach to this since the 80s although started out inadvertently due to time constrains bears it out although yet to test it on coral but then that's just another invert seeking nutrients we painstakingly try removing then adding back because some study mentioned these narrow ranges or this belief one needs to read nitrates to confirm ammonia present in adequate quantity. Seems like a big circle jerk to me although purely anecdotally which is how most operate their reefs.

 

[sixty_reefer]

This has to be one of the most pseudo-intellectual and artificially pedantic reefing "conversations" I think I have ever seen. We are 9 pages in and I don't think anybody has any idea (we are low IQ I suppose) what the actual point is.

I understand how this discussion might come across as overly complex. The goal here was to explore a different perspective, but it seems it may gone off-track. If there’s anything specific that needs clarification, feel free to point it out.

 

[areefer01]

what the actual point is.

I've come to the conclusion that they just want to say things.

 

[rishma]

I don't subscribe to this theory nitrates and phosphates must be maintained within a narrow range being that's not what occurs in nature. .

or this belief one needs to read nitrates to confirm ammonia present in adequate quantity.

I think phosphate and nitrate on healthy natural reefs do stay in a pretty tight range, lower than what we aim for in our tanks. I am not sure what you mean here. While a good range in a tank is wider than the ocean, with P in particular, it tends to be fairly narrow and measured in ppb! That’s pretty tight to me. I think the hobby has relaxed a bit in recent years and understanding success if possible over a range of phosphate and nitrate, but it’s still pretty narrow in my opinion. I guess it’s all relative.

Regarding wanting to detect nitrate to know you are not nitrogen limited…is it absolutely necessary? No, absolutes are rarely correct in this hobby. Is it darn helpful when carbon dosing? I think it is and will add a bit of ammonia if my nitrate drops really low.

 

[GARRIGA]

I think phosphate and nitrate on healthy natural reefs do stay in a pretty tight range, lower than what we aim for in our tanks. I am not sure what you mean here. While a good range in a tank is wider than the ocean, with P in particular, it tends to be fairly narrow and measured in ppb! That’s pretty tight to me. I think the hobby has relaxed a bit in recent years and understanding success if possible over a range of phosphate and nitrate, but it’s still pretty narrow in my opinion. I guess it’s all relative.

Regarding wanting to detect nitrate to know you are not nitrogen limited…is it absolutely necessary? No, absolutes are rarely correct in this hobby. Is it darn helpful when carbon dosing? I think it is and will add a bit of ammonia if my nitrate drops really low.

My point being N & P not detective on a reef yet target rich being fish constantly feeding and excreting detritus and ammonia.

Perhaps heavy in and letting that settle through proper filtration vs excavating nutrients hoping to maintain any range.

Tank heavily fed is likely never ammonia challenged even if nitrates don’t register.

 

[rishma]

My point being N & P not detective on a reef yet target rich being fish constantly feeding and excreting detritus and ammonia.

Perhaps heavy in and letting that settle through proper filtration vs excavating nutrients hoping to maintain any range.

Tank heavily fed is likely never ammonia challenged even if nitrates don’t register.

Ok, I can buy that a heavily fed tank is unlikely to be N limited. I don’t feed that heavily because heavy out on a tiny AIO tank is tough and phosphates become hard to manage. Cheers

 

[Randy Holmes-Farley]

Most tanks with detectable levels of N and P in the water are going to be carbon limited. That’s why dosing a carbon source into the aquarium can help remove N and P.

It seems that if you have testable levels of N and P, you are very probably C limited. What else is it that you would like to know?

I wasn’t asking a question, I was stating my opinion.

I certainly agree with you. So are most tanks with no kit detectable nutrients going to be carbon limited, as is the ocean.

 

[Randy Holmes-Farley]

I can see that this thread is already way off the rails, but I have a semi-serious question on the topic...it is my impression that home nitrate tests are low precision/ accuracy and ICP results are slow and expensive. Therefore, I don't track N. Same goes for DOC. If we have 3 variables N, P, and C, 2 unknowns, and 1 "ratio" how do we formulate a solution?

Even if I could pretend to understand the topic, I don't think we really have reliable data for making decisions?

A solution to what problem?

 

[Randy Holmes-Farley]

If there isn’t any N or P in the system we couldn’t say for sure if C is more abundant than during stable conditions without knowing the system environment.
If we talking of Ultra low residual that can only be tracked via icp, if you have an absolute zero in Nitrate or Phosphate is more than likely for the system to not be carbon limited.

If we were to compare every dinoflagellate case that we see now days, we could observe that the blooms are caused in majority of the situation for moments in time were a nutrient become limited in a particular environment.

There are zero reef tanks with zero dissolved sources of N or P. I don’t see a benefit to discussing impossible hypotheticals.

 

[Tavero]

Redfield has several uses in science one of my favourite implementations of Redfield ratio is to determine nutrient limitations in aquaria.

With the main reference ratio being 16:1, this number is widely agreed between aquarists including many experts on this forum for the assimilation rate of N and P for heterotrophic bacteria during carbon dosing and it’s also agreed between several expert aquarist that if a reef tank is limited by P for example that we cannot lower nitrates using organic carbon due to the bacteria becoming limited in one nutrient.

My point being that would we gain more as aquarist by understanding how Redfield nutrient limitations work?

Some examples were Redfield could be used as a example could be in the battle against nuisances algae like GHA as many folks do tend deplete a system from phosphates causing their biological filter to be unable to assimilate nutrients that could compete with the algae for example.

There is many other ways that I can think were we could use Redfield nutrient limitations in order to improve coral growth and reducing nuisances although I would like to hear your thoughts.


If you read all this way please don’t just post saying that you like to keep your No3 and Po4 at the same ratio as Redfield as that’s not how it’s used, that’s just a preference on how someone keeps their residual N and P, sorry had to be said.

Forget about redfield ratio. It isn't relevant for reef tanks.
I haven't read the whole thread because it already has 9 pages so maybe someone has already mentioned it but redfield ratio only applies for deep sea animals.

"The Redfield ratio or Redfield stoichiometry is the consistent atomic ratio of carbon, nitrogen and phosphorus found in marine phytoplankton and throughout the deep oceans."

Do we keep deep sea animals? No we don't.

 

[sixty_reefer]

There are zero reef tanks with zero dissolved sources of N or P. I don’t see a benefit to discussing impossible hypotheticals.

I meant Nitrate and Phosphate, N and P abbreviations have been so missed used that I end up making that same mistake

 

[sixty_reefer]

Forget about redfield ratio. It isn't relevant for reef tanks.
I haven't read the whole thread because it already has 9 pages so maybe someone has already mentioned it but redfield ratio only applies for deep sea animals.

"The Redfield ratio or Redfield stoichiometry is the consistent atomic ratio of carbon, nitrogen and phosphorus found in marine phytoplankton and throughout the deep oceans."

Do we keep deep sea animals? No we don't.

I think a few folks vaguely touched the subject. Then again they also haven’t read the discussion proposed here.

 

[sixty_reefer]

I wasn’t asking a question, I was stating my opinion.

I certainly agree with you. So are most tanks with no kit detectable nutrients going to be carbon limited, as is the ocean.

Is carbon limited the right word to describe a reef tank? Or could there be a better word to describe as it’s my understanding that a normal reef thank has a constant influx of carbon that is added to the water column via the fish waste, uneaten food, coral and invertebrate excretions, some bacteria, dead organisms, macro and micro algae's decomposition etc..

 

[BeanAnimal]

I understand how this discussion might come across as overly complex. The goal here was to explore a different perspective, but it seems it may gone off-track. If there’s anything specific that needs clarification, feel free to point it out.

Respectfully, from where I sit the conversation is not being limited by any "complexity" that needs clarification.

The moving goal posts and hubris are what most of us are struggling to understand.

Is carbon limited the right word to describe a reef tank? Or could there be a better word to describe as it’s my understanding that a normal reef thank has a constant influx of carbon that are added to the water column via the fish waste, uneaten food, coral and invertebrate excretions, some bacteria, dead organisms, macro and micro algae's etc..

Careful, you are going to end up contradicting yourself again and that will require another pivot....

 

[sixty_reefer]

Respectfully, from where I sit the conversation is not being limited by any "complexity" that needs clarification.

The moving goal posts and hubris are what most of us are struggling to understand.

If there are any specific examples of shifting expectations could you point them out to me? I’d be happy to address them.

 

[Randy Holmes-Farley]

I meant Nitrate and Phosphate, N and P abbreviations have been so missed used that I end up making that same mistake

Then I repeat my original assertion;

I believe all reef tanks regardless of any reading on a nitrate or phosphate kit are carbon limited, just like the ocean.

All that means is that if you add readily metabolized organics like acetate, bacteria will consume them.

Of course, if one adds a lot of organic, something else may become limiting. N, P, iron, etc.

 

[Randy Holmes-Farley]

Is carbon limited the right word to describe a reef tank? Or could there be a better word to describe as it’s my understanding that a normal reef thank has a constant influx of carbon that is added to the water column via the fish waste, uneaten food, coral and invertebrate excretions, some bacteria, dead organisms, macro and micro algae's decomposition etc..

If you want to narrow the question and answer down from a reef tank to a single organism, then the answer may be different.

 

[sixty_reefer]

If you want to narrow the question and answer down from a reef tank to a single organism, then the answer may be different.

We could narrow it dow a little further to fish food as most of the carbon is used by the fish for energy, the more complex forms of carbon such as fibre will pass through their digestive system without being fully broken down, this imo will contribute for a influx of carbon that can be used by bacteria.