Acropora and the Redfield Ratio

rlkilwil · Oct 5, 2021

Hey everyone! I've been listening to a lot of podcasts and learning a lot lately and I'm wondering where you guys sit on the issue of the Redfield Ratio! (For those who don't know, the RR is basically the idea that the ideal levels of nitrate and phosphate will be in a 10:1 ratio, whether they're high or low.)

Do you guys keep your nutrients close to that ratio? What do you guys think about the RR in regards to acropora tissue growth/coloration? Do you notice a difference in your coral growth when nutrients fall out of proportion??

For some context, I'm growing my first set of acros, and loving it! I'm just trying to learn more, and see what experience you guys have with this concept!

MnFish1 · Oct 5, 2021

The 'Redfield ratio' is not meant to be used in this manner. I would not pay attention to it - with regards to my tank - nor do I. It (according to Redfield) - is not the water that creates the Redfield ratio - but rather the inhabitants in the water. You cannot create (IMHO) a Redfield ratio.

captainbeardly · Oct 5, 2021

MnFish1 said:
The 'Redfield ratio' is not meant to be used in this manner. I would not pay attention to it - with regards to my tank - nor do I. It (according to Redfield) - is not the water that creates the Redfield ratio - but rather the inhabitants in the water. You cannot create (IMHO) a Redfield ratio.

You’re right you can’t create the red field ratio but I beige it’s more of a starting point to where your corals would be happy then hold those numbers solid

MnFish1 · Oct 5, 2021

captainbeardly said:
You’re right you can’t create the red field ratio but I beige it’s more of a starting point to where your corals would be happy then hold those numbers solid

No - I disagree its not. The Redfield ratio is the ratio of Nitrogen and Phosphorous in zooplankton in the open ocean. Its not the ratio of Nitrate and Phosphate

Acrofiend · Oct 5, 2021

It’s more number chasing than anything. Best tip I’ve learned in this is hobby is not to chase numbers. Anything over 0 is good.

Chrisv. · Oct 5, 2021

Plenty of people keep acros in water they draw off of their septic system. There was a whole thread about it this weekend. Beautiful, bright acros.

Scdell · Oct 5, 2021

Chrisv. said:
Plenty of people keep acros in water they draw off of their septic system. There was a whole thread about it this weekend. Beautiful, bright acros.

I don't even know what to say about this.

Scdell · Oct 5, 2021

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Charlie’s Frags · Oct 5, 2021

Chrisv. said:
Plenty of people keep acros in water they draw off of their septic system. There was a whole thread about it this weekend. Beautiful, bright acros.

I don’t have a septic tank

ScottB · Dec 17, 2021

Charlie’s Frags said:
I don’t have a septic tank

That may be true, but are you denying that you have a manifold on your sewage waste line running into your sump?

Perhaps I've been mislead, but I kinda thought that was the common perception around here...

ScottB · Dec 17, 2021

I don't follow the RR debate much either, but I do like to keep a balance between NO3 & PO4. One system runs lower (2 : .05) and the other a little richer at 6 : .06.

I find I get a little cyano starting when one nutrient runs away from the other too much. I can't say it makes a meaningful difference to my acro health TBH.

Charlie’s Frags · Dec 17, 2021

ScottB said:
That may be true, but are you denying that you have a manifold on your sewage waste line running into your sump?

Perhaps I've been mislead, but I kinda thought that was the common perception around here...

Troll alert

X-37B · Dec 17, 2021

Best advice I could give and its what I follow is.
Po4<.1
No3 <5.
This seems to work for most systems.
Just keep everthing stable.

GARRIGA · Dec 17, 2021

Know this much. Not until I raised my phosphates did my nitrates drop. Now I keep them below 5 ppm and 0.25 ppm. No acros yet and just testing different scenarios.

Recently had to apply PhosGuard to eliminate silicates and my phosphates seemed closer to zero than the lowest setting. I’ll be getting a Hanna checker soon to get more accurate on both but my nitrates are now around 20 ppm. Phosphates still under 0.25 ppm. Feeding flakes to naturally add phosphates but will resort to NeoPhos if needed.

I’m curious as to whether maintaining a close ratio more beneficial then trying to seek phosphates of .03 ppm. I’m just not detailed enough to aim for such precision nor believe nature is either. Curious as to the test done to seek such low numbers were done in the general area or next to the corals. Gotta believe with all those fish breathing and pooping and nature doing it’s thing if those nutrient levels might be higher.

Frozen food seems the most practical to introduce the stated ratio.

Scdell · Dec 17, 2021

I've been scolded on here about trying to follow the RR.
Its all about chasing numbers.
Not necessarily a good thing.
Numbers can fool you. And deceive you.
Find a spot where your tank looks good and is actually doing good.
Po4 is most misleading. You can get a low reading with algae growing.
And yes.... You need both no3 and po4 to keep each in check.
It's all a fine line. Uln is not a game for the faint of heart.

MnFish1 · Dec 17, 2021

Does anyone know what the red field ratio is lol it has nothing to do with our tanks imho

Scdell · Dec 17, 2021

MnFish1 said:
Does anyone know what the red field ratio is lol it has nothing to do with our tanks imho

Prey tell.... Prove it with facts not theory. I'm all ears.

J1a · Dec 17, 2021

Scdell said:
I've been scolded on here about trying to follow the RR.
Its all about chasing numbers.
Not necessarily a good thing.
Numbers can fool you. And deceive you.
Find a spot where your tank looks good and is actually doing good.
Po4 is most misleading. You can get a low reading with algae growing.
And yes.... You need both no3 and po4 to keep each in check.
It's all a fine line. Uln is not a game for the faint of heart.

I think the matter here is not just about chasing numbers, but perhaps chasing a wrong set of numbers.

The C:N

:Fe ratios we need to supply to the aquarium depends on the things we want to keep in the aquarium. If we keep chaeto, for example, we will have to supply so much more nitrogen element than phsophorus element.

Scdell · Dec 17, 2021

J1a said:
I think the matter here is not just about chasing numbers, but perhaps chasing a wrong set of numbers.

The C:N:Fe ratios we need to supply to the aquarium depends on the things we want to keep in the aquarium. If we keep chaeto, for example, we will have to supply so much more nitrogen element than phsophorus element.

This new stoichiometric ratio states that the ratio should be 106 C:16 N:1 P:0.1-0.001 Fe. The large variation for Fe is a result of the significant obstacle of ships and scientific equipment contaminating any samples collected at sea with excess Fe.

J1a · Dec 17, 2021

Scdell said:
This new stoichiometric ratio states that the ratio should be 106 C:16 N:1 P:0.1-0.001 Fe. The large variation for Fe is a result of the significant obstacle of ships and scientific equipment contaminating any samples collected at sea with excess Fe.

Yes. However, the redfield ratio does not measure the ratio of elements in seawater.

It measures the phytoplanktons at/near the surface, as well as the deep pools of nutrients in ocean. Neither of which is what we focus on in a reef aquarium.

There is a recent study on chaeto

https://www.kmae-journal.org/articl...UQFnoECBIQAQ&usg=AOvVaw0WzsHXuYPeUo9-iJPYgR4b

It's a good read.