Redfield Isn’t Your Friend

[rtparty]

Redfield wasn’t even invited to the party but someone brought him anyway. He is now the unwelcome guest that won’t leave.

Thanks for the article @BeanAnimal

https://beananimal.com/articles/the-redfield-ratio-doesnt-mean-what-you-think-the-reef-tank-buffet/

 

[That Crusso Kid]

Redfield wasn’t even invited to the party but someone brought him anyway. He is now the unwelcome guest that won’t leave.

Thanks for the article @BeanAnimal

https://beananimal.com/articles/the-redfield-ratio-doesnt-mean-what-you-think-the-reef-tank-buffet/

My only issue with @BeanAnimal 's article is that it's only 6:27AM here and now I want a burger. It also causes me to wonder what will happen to the ratio if I add cheese to the burger.

 

[rtparty]

My only issue with @BeanAnimal 's article is that it's only 6:27AM here and now I want a burger. It also causes me to wonder what will happen to the ratio if I add cheese to the burger.

If you add bacon, it becomes a breakfast food.

 

[VintageReefer]

If you add bacon, it becomes a breakfast food.

 

[56longroof]

Charles Delbeek has a great video on the Redfield ratio.

 

[BriDroid]

Charles Delbeek has a great video on the Redfield ratio.

The N:P molar ratio. I don’t really shoot for it, but when my tank runs ~50:1 molar ratio, my glass and rocks are the cleanest

 

[Randy Holmes-Farley Verified Community Expert]

The N:P molar ratio. I don’t really shoot for it, but when my tank runs ~50:1 molar ratio, my glass and rocks are the cleanest

So that applies if nitrate is 500 ppm and phosphate is 10 ppm?

Or does it apply at the absolute values you actually used to obtain that ratio, in which case targeting those absolute values (which is what I recommend) will attain exactly the same result. :)

No one is saying one should not be at the Redfield ratio if the absolute values are appropriate, what folks are saying is that the ratio alone is a poor way to set targets.

 

[rtparty]

The N:P molar ratio. I don’t really shoot for it, but when my tank runs ~50:1 molar ratio, my glass and rocks are the cleanest

Here’s something I found interesting when running numbers years ago. A little thought exercise I did.

Let’s pick some easy numbers and test kits that give us resolution and precision information. Let’s just go with 50ppm nitrate and 1ppm phosphate for the ~50:1 ratio.

The Hanna Nitrate HR has a precision of ±2 ppm ±5% of reading @ 77°F (25°C). So 50ppm is actually anything from 45.6ppm up to 54.6ppm.

The Hanna Phosphate checker has a precision of ±0.04 ppm (mg/L) ±4% of reading @ 25°C. Meaning 1ppm is anything from 0.92ppm up to 1.08ppm.

The ratio could be anything from 42:1 to 59:1 and all be within the margin of error for the test kits.

 

[BriDroid]

Like I said, I don’t aim for it, just when I test and I fall close to his 50:1 ratio, my algae looks the best.

 

[Randy Holmes-Farley Verified Community Expert]

I was inspired to post this article of what I consider a better approach to nutrients and trace elements than the Redfield ratio:

Forget Redfield, Liebig is the Man!

https://www.reef2reef.com/threads/forget-redfield-liebig-is-the-man.1151779/

 

[sixty_reefer]

As usual it seems that both sides of the discussion carry on focusing on residual N and P. How can this be beneficial for either side of the discussion?
Residual N and P is just what’s not been used in an aquarium at the moment of given water testing.
If folks really wanna finish this discussion someone needs to come forward with proofing that a balanced stable reef tank has a nutrient export ratio that will differ from Redfield ratio for the make up of seawater.
Until then both sides will just be accomplices of spreading misinformation.

For folks reading this kind of threads, I would seriously advise to ignore both sides of the discussion and just keep your tank as stable as you can, nutrient ratios can help resolve certain problems but this ones are all general knowledge in the hobby you don’t need a residual nutrient ratio that matches Redfield for anything aquarium related imo.

 

[BeanAnimal]

As usual it seems that both sides of the discussion carry on focusing on residual N and P. How can this be beneficial for either side of the discussion?
Residual N and P is just what’s not been used in an aquarium at the moment of given water testing.
If folks really wanna finish this discussion someone needs to come forward with proofing that a balanced stable reef tank has a nutrient export ratio that will differ from Redfield ratio for the make up of seawater.
Until then both sides will just be accomplices of spreading misinformation.

For folks reading this kind of threads, I would seriously advise to ignore both sides of the discussion and just keep your tank as stable as you can, nutrient ratios can help resolve certain problems but this ones are all general knowledge in the hobby you don’t need a residual nutrient ratio that matches Redfield for anything aquarium related imo.

Redfield has nothing to do with stability or “what’s left over.” You’re applying an average of what’s in the tissue of a subset of organisms on the open ocean to a closed system.

A reef tank isn’t phytoplankton driven, it isn't the open ocean.

We have bacteria, algae, coral, and abiotic precipitation, with variable import and export that don't scale to the open ocean model. None of this shares a fixed N:P consumption ratio. There is no meaningful application of Redfield to water column N:P.

Residual nitrate and phosphate are relevant to input, consumption, and export balance. This isn’t a fixed ratio, be it Redfield or anything else.

Demanding “proof” that export ratios differ from Redfield doesn’t mean anything. We’ve covered this exhaustively. Redfield is an average based on phytoplankton tissue composition in the open ocean. It has nothing to do with water column levels or overall system balance, especially in a closed system.

 

[rtparty]

nutrient ratios can help resolve certain problems but this ones are all general knowledge in the hobby you don’t need a residual nutrient ratio that matches Redfield for anything aquarium related imo.

Which ratio fixes which problem?

 

[sixty_reefer]

Which ratio fixes which problem?

The import/export ratio is the only ratio that matters and the only tool we have to know that our system are working at a good ratio is the residual N and P as long as those two parameters are stable then no other ratio needs chasing.

 

[sixty_reefer]

Redfield has nothing to do with stability or “what’s left over.” You’re applying an average of what’s in the tissue of a subset of organisms on the open ocean to a closed system.

A reef tank isn’t phytoplankton driven, it isn't the open ocean.

We have bacteria, algae, coral, and abiotic precipitation, with variable import and export that don't scale to the open ocean model. None of this shares a fixed N:P consumption ratio. There is no meaningful application of Redfield to water column N:P.

Residual nitrate and phosphate are relevant to input, consumption, and export balance. This isn’t a fixed ratio, be it Redfield or anything else.

Demanding “proof” that export ratios differ from Redfield doesn’t mean anything. We’ve covered this exhaustively. Redfield is an average based on phytoplankton tissue composition in the open ocean. It has nothing to do with water column levels or overall system balance, especially in a closed system.

Different environments but they both have to abide by the same rules.
Once you able to calculate import/export you will find that your ratios may not be to far from it

 

[areefer01]

Charles Delbeek has a great video on the Redfield ratio.

No, he doesn't. He specifically says it is not the Redfield and how the Refield has nothing to do with corals. His most recent talk at High Tide he discusses this again.

 

[BeanAnimal]

The import/export ratio is the only ratio that matters and the only tool we have to know that our system are working at a good ratio is the residual N and P as long as those two parameters are stable then no other ratio needs chasing.

You are stuck on ratios. Balance and a fixed ratio are not the same thing. As the system grows, the ratio of consumed N:P will vary. If you think balance (stability) is required, then import and export would have to be regularly adjusted to keep whatever water column N:P you decided on. But as we’ve discussed endlessly, the N:P in the water has nothing to do with the N:P consumed by different pathways.

Different environments but they both have to abide by the same rules.
Once you able to calculate import/export you will find that your ratios may not be to far from it

You can't calculate import or export in any meaningful way. You are chasing a lark to apply Redfield to consumption and/or availability, something it was never intended to apply to.

 

[rtparty]

The import/export ratio is the only ratio that matters and the only tool we have to know that our system are working at a good ratio is the residual N and P as long as those two parameters are stable then no other ratio needs chasing.

You didn't answer the question.

What is the ratio? How do we directly influence and keep those ratios?

 

[56longroof]

No, he doesn't. He specifically says it is not the Redfield and how the Refield has nothing to do with corals. His most recent talk at High Tide he discusses this again.

How was his talk not relevant? He clearly dispelled the Redfeild ratio.

 

[areefer01]

How was his talk not relevant? He clearly dispelled the Redfeild ratio.

You posted above "Charles Delbeek has a great video on the Redfield ratio" to which my reply was no, he doesn't. Unless he has one that is specifically talking to that subject. If you are referencing his talk at High Tide Aquatics in December, 2024 he is talking about the N:P molar ratio, his thoughts, peers in public aquaria, and a couple of studies done in a couple oceanic areas.

He is not talking about the Redfield ratio other than to articulate that the Redfield ration is for phytoplankton and NOT CORAL. This is noted up front of the talk about 12 to 15 minutes in. Why? Because when he talks about this it is often times mentioned by someone to which he will quickly clarify and correct. You see this often because Paletta sites ratios a lot...

Maybe I am nit picking or getting hung up on verbiage but the talk in December has nothing to do with the Redfield Ratio which he clearly states.