The Redfield Ratio

[sabbath]

It is appearing to me from my carbon dosing journeys. That if we maintain our No3 around .25-.5 we will end up with our Po4 at around .015-.03 (16:1).
What are your thoughts and experiences?
Thanks

[tmz]

The redfield ratio doesn't really apply.
The various bacteria have differnt ratios of CNP. Further in addition to consuming N for growth ,they use some more of it in anearobic respiration resulting in a a greater reductin in N via NO3 breakdown and N2( nitrognen gas) releasing.

These reactions will be different in different systems depending on a number of variables such as surface area, nutrient levels, type and amount of carobn source, ph and on ad on.

FWIW,In my system PO4 is 05ppm with NO3 at around 0.2ppm. I dose vodka and vinegar but also run refugia,cryptic areas, small amounts of GFO and a good amount of granulatedactivated carbon.

[sabbath]

Originally Posted by tmz

The redfield ratio doesn't really apply.
The various bacteria have differnt ratios of CNP. Further in addition to consuming N for growth ,they use some more of it in anearobic respiration resulting in a a greater reductin in N via NO3 breakdown and N2( nitrognen gas) releasing.

These reactions will be different in different systems depending on a number of variables such as surface area, nutrient levels, type and amount of carobn source, ph and on ad on.

FWIW,In my system PO4 is 05ppm with NO3 at around 0.2ppm. I dose vodka and vinegar but also run refugia,cryptic areas, small amounts of GFO and a good amount of granulatedactivated carbon.

Interesting Tom,
I would like to as with many others I'm sure, get by without running GFO. So if what you are saying is true. I now wonder what conditions will work to our favor?
Higher Ph, more porous rocks. more or less rock. type of carbon source, add a bacteria...
Thanks

[tmz]

It's true,ime and research. I wouldn't offer it otherwise.
I don't add bacteria at all ; there are plenty of naturally occuring bacteria which will remain viable . PO4 will go below .08ppm for me wthout gfo. A small amount drops the last bit I want but I use much less than before dosing. More surface area matters in my opinion. Systems vary, I feed al ot. Less ,with lower PO4 foods might get lower PO4 level without a reducer.like gfo.

[HighlandReefer]

Keep in mind that the Redfield Ratio applies to total Nitrogen and total Phosphorous, not just inorganic nitrate and phosphate. Total carbon as well not just vodka or vinegar for example.

Redfield Ratio: C:N:P = 106:16:1

The Redfield ratio applies to a general average of all the microbial life found in the ocean, not just bacteria.

Many bacteria can utilize organic forms of nitrogen and phosphorous when nitrate and phosphate are in low supply. Bacteria can utilize other forms of organic carbon as well.

This can make the use of the Redfield Ratio in a reef tank almost useless, but does let us know that bacteria utilize a lot more N than P to grow and reproduce.

[Randy Holmes-Farley]

I think there are too many different ways to import and export N and P from aquaria, some of which have the two tied together in some way and some of which do not, to really make any strong connection between the two.

[Big E]

Trying to strive for 16:1 may be useless, but montoring N & P levels on your tank for which ratio your corals look & grow best could be useful.

I've read a lot of SPS tanks having problems when the ratios are skewed. It usually seems to be when N is too low in reference to P. Pellet users have run across this more the the carbon dosers.

[sabbath]

OK, So if true that there is a ratio of some level going on. Then I wonder if we could play with the type of live rock that we use to help balance our P and N levels. Like using larger more dense rocks to lower the N level. To lower the P use porous rubble type rocks.

[HighlandReefer]

N & P usage ratio will remain pretty much the same as this is the ratio that the organisms within a reef tank use them.

For example if you use a very dense rock, you will only get organisms growing on the surface which is decreased using this rock. It will not have much effect on the organisms suspended in the water column and the rest of the tank. With less surface area you should get less usage of N & P, but at a similar ratio.

If you use a porous rock, the surface area is greatly increased which allows more organisms to grow on its surfaces, which in theory should increase the usage of N & P, but still at a similar ratio.

IMHO, the bottom line is that the N & P should be in an appropriate ratio in your water column, meaning if the P is much higher than the N, you would want to reduce the P down to an appropriate level using a phosphate binding material like GFO.

If N is very high and P is undetectable, the debate is whether there is enough P available for growth. If not you will not get a decrease in N. With the amount of P added in fish foods alone & excreted by fish, it is possible that this source may provide ample P to reduce the nitrate levels, if enough fish food is added. If not then perhaps adding some P would be beneficial. As long as you know there is some P in there, you feel your equipment used for testing gets a reading (this is debatable), then there is P available for reducing N and I don't feel you would need to add more. This is why I question whether you really need to add P when nitrates are high.

[Randy Holmes-Farley]

Bear in mind that carbon dosing can use a lot more N than P, even by Redfield sorts of ratios, because of nitrate potentially being converted into N2 in low O2 areas like sand beds or in live rock. That process is driven by metabolism of organic matter in low O2 areas, so is potentially greatly enhanced by organic carbon dosing..

By that means, one can essentially eliminate nitrate will still having substantial P, and that, IMO, is why many folks find it desirable to use other methods at the same time, like GFO or growing macroalgae.

Alternatively, some folks find it desirable to dose nitrate under the scenario, along for more bacterial growth than the carbon dosing alone promotes, and that allows P to also be consumed.

[HighlandReefer]

I know in my case, I had a tank wipe out due to increased heat. I ran lots of GFO, with no detectable phosphate, but my nitrate went up to around 80 ppm. I began vinegar dosing which reduced my nitrate level down to undetectable while all along maintaining an undetectable phosphate reading using a Hach PO-19 phosphate kit.

[Yuri Barros]

I don´t have experience in Redfield Ratio....................but I have some thoughts...................

This easiest formula is to multiply the P value...........(X10)..................

For exemple............if you have P = 0.03mg/l...............(x10).......your Nitrate level should be 0.3mg/l....................

Then the ideal proportion is 16...............

So............N:P

(Nitrate Level . 1.5) / P

0.3.15 /0.03 = 15

When your P is undetectable...............by the Test.............it´s OK............you can assume that the level is about 0.03................

Remember that no P..............means no Life.................so...............0.03 is acceptable value...............

Then you have to down the Nitrate level................adding Biopellets............

When Nitrate level drops................you have to regulate it............to just a little above Zero.................

But not zero..................zero means unbalance in Redfield Ratio............

When the Nitrate test show "zero"................you just reduce the amount of Biopellets in the Sistem................to raise Nitrate level to 0.3mg/l..............

That´s good Level for SPS Corals..................

I studied Redfield Ratio to avoid Cyanos......................

But I don´t have experience.................

I´m just start to study Redfield Ratio....................

It´s just thoughts...............................

[disc1]

I think you need to check your keyboard. It appears that the period key is stuck.

The Redfield ratio applies to the organisms in the water. Applying it to the levels of free nutrients in the water is a gross misuse of the number. There are other processes that remove nitrate besides bio-assimilation.

[tmz]

Surface area and the other variables in a particular aquarium influence the bacterial activity along with CNP levels and their proportions.
N or P deficiencies are unlikely in fed tanks with fish but may occur particularly when the starting point is skewed to one or the other( ie to N or P or C). If the tank is very high in nitrates or phosphate ,reducing those levels before beginning organic carbon dosing is helpful ,ime. Then an organic carbon dosing level may found for a particular tank in balance with the routine imports from feeding ,etc.
It's easier to select a fixed dosing level with soluble organic carbon sources like vodka and/or vinegar than it is with pellets where the measure is indirect and subject to reactor dynamics such as flow rates, clogs, variable ph , variable movement of monomers from the reactor to the water column, a longer degradation process ,etc.

The nature of the organic carbon effects the the bacterial activity and the type and mix of organics in a tank. I prefer organics closer, process wise, to acetate ,ie, ethanol and/or vinegar to carbohydrates and sugars.

[Yuri Barros]

Thanks for the replies....................

My approach is Algae and Red Slime control..................using the Redfield Ratio.......................

But I don´t now if it works......................

I just start to read these articles.....................


http://www.aquariumhobby.nl/zoetwate.../redfield.html

http://buddendo.home.xs4all.nl/aquar...dfield_eng.htm

[Habib]

The first link is in Dutch.............

Are you from Holland?...............

[tmz]

When I was in Amsterdam 40 +years ago, I don't remember folks using lots of ............. in their writings. But then I don't speak the language, unfortunately.............

[Habib]

Originally Posted by tmz

When I was in Amsterdam 40 +years ago, I don't remember folks using lots of ............. in their writings. But then I don't speak the language, unfortunately.............

That was the hippy/flowerpower era. So I think they wrote things differently then.

I lived/live about 60 miles eat of Amsterdam. Can't be a much larger distance because 100 miles from Amsterdam one would end in the sea or in Belgium or Germany depending on which direction.

[Yuri Barros]

I´m Brazilian................

Nice info...........that you know Holland.........................

Holland is knowed to have amazing Planted Aquariums...............

I´m not able to read this Article properly.........................but maybe there are some important information about Redfield Ratio.................related with Algae Control...............

I´m tring to find some infos.........about Cyanos (Red Slime) control............using the Redfield Ratio................

I don´t know much about that.............

[disc1]

Originally Posted by Yuri Barros

I´m tring to find some infos.........about Cyanos (Red Slime) control............using the Redfield Ratio................

The Redfield Ratio would help you approximate how much nutrient you could expect to get from a certain amount of cyano if you ground it up.

People who try to apply it to control of anything are absolutely not understanding what it means. The number really doesn't apply to that.

[timvdb]

This is from a website referred to earlier in the forum. Ay thoughts?



"He read something about the so called Redfield ratio. That is the ratio between the quantity of nitrogen and phosphorus in the water. Several researchers have used the Redfield ratio to see what the influence is of different values on the occurrence of various types of algae. An article of Bulgakov et al. has been translated by Agnes Zaalinto Dutch; my thanks to her.



It seems that the change of getting green algae is big, if comparatively much nitrogen and little phosphorus is in the water. In reverse, little nitrogen c.q. a lot of phosphorus leads to a big change that you will start growing blue-green algae. The optimum seems to be at the proportion nitrogenhosphorus = 16:1. Which means a Redfield ratio of 16."




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[HighlandReefer]

Hobbyists measure nitrate and phosphate only normally. Cyano are a different breed than algae. They can fix nitrogen from the atmosphere, so how do you control this form of N (Nitrogen) for Cyano. They also can use organic phosphorous in addition to inorganic phosphate, so measuring phosphate only does not give you the complete picture for P sources in your tank for cyanobacteria.

From Wiki:

"Nitrogen fixation

Cyanobacteria cultured in specific media. Cyanobacteria can be helpful in agriculture as they have the capability to fix atmospheric nitrogen to soil.
Cyanobacteria include unicellular and colonial species. Colonies may form filaments, sheets or even hollow balls. Some filamentous colonies show the ability to differentiate into several different cell types: vegetative cells, the normal, photosynthetic cells that are formed under favorable growing conditions; akinetes, the climate-resistant spores that may form when environmental conditions become harsh; and thick-walled heterocysts, which contain the enzyme nitrogenase, vital for nitrogen fixation. Heterocysts may also form under the appropriate environmental conditions (anoxic) when fixed nitrogen is scarce. Heterocyst-forming species are specialized for nitrogen fixation and are able to fix nitrogen gas into ammonia (NH3), nitrites (NO− 2) or nitrates (NO− 3) which can be absorbed by plants and converted to protein and nucleic acids (atmospheric nitrogen is not bioavailable to plants).

Rice plantations utilize healthy populations of nitrogen-fixing cyanobacteria (Anabaena, as symbiotes of the aquatic fern Azolla) for use as rice paddy fertilizer.[4]


Cyanobacteria are arguably the most successful group of microorganisms on earth. They are the most genetically diverse; they occupy a broad range of habitats across all latitudes, widespread in freshwater, marine and terrestrial ecosystems, and they are found in the most extreme niches such as hot springs, salt works, and hypersaline bays. Photoautotrophic, oxygen-producing cyanobacteria created the conditions in the planet's early atmosphere that directed the evolution of aerobic metabolism and eukarotic photosynthesis. Cyanobacteria fulfill vital ecological functions in the world's oceans, being important contributors to global carbon and nitrogen budgets."

– Stewart and Falconer[5]

[HighlandReefer]

To say the least, cyanobacteria are a tough hombre to defeat and control in some cases when they become pests.


More from Wiki:

"Ecology

Many cyanobacteria also form motile filaments, called hormogonia, that travel away from the main biomass to bud and form new colonies elsewhere. The cells in a hormogonium are often thinner than in the vegetative state, and the cells on either end of the motile chain may be tapered. In order to break away from the parent colony, a hormogonium often must tear apart a weaker cell in a filament, called a necridium.

Each individual cell of a cyanobacterium typically has a thick, gelatinous cell wall. They lack flagella, but hormogonia and some species may move about by gliding along surfaces. Many of the multi-cellular filamentous forms of Oscillatoria are capable of a waving motion; the filament oscillates back and forth. In water columns some cyanobacteria float by forming gas vesicles, like in archaea. These vesicles are not organelles as such. They are not bounded by lipid membranes but by a protein sheath.

Some of these organisms contribute significantly to global ecology and the oxygen cycle. The tiny marine cyanobacterium Prochlorococcus was discovered in 1986 and accounts for more than half of the photosynthesis of the open ocean.[6] Many cyanobacteria even display the circadian rhythms that were once thought to exist only in eukaryotic cells (see bacterial circadian rhythms)."


"Many cyanobacteria are able to reduce nitrogen and carbon dioxide under aerobic conditions, a fact that may be responsible for their evolutionary and ecological success. The water-oxidizing photosynthesis is accomplished by coupling the activity of photosystem (PS) II and I (Z-scheme). In anaerobic conditions, they are also able to use only PS I — cyclic photophosphorylation — with electron donors other than water (hydrogen sulfide, thiosulphate, or even molecular hydrogen[8]) just like purple photosynthetic bacteria. Furthermore, they share an archaeal property, the ability to reduce elemental sulfur by anaerobic respiration in the dark. Their photosynthetic electron transport shares the same compartment as the components of respiratory electron transport. Their plasma membrane contains only components of the respiratory chain, while the thylakoid "

[disc1]

Originally Posted by timvdb

This is from a website referred to earlier in the forum. Ay thoughts?



"He read something about the so called Redfield ratio. That is the ratio between the quantity of nitrogen and phosphorus in the water. Several researchers have used the Redfield ratio to see what the influence is of different values on the occurrence of various types of algae. An article of Bulgakov et al. has been translated by Agnes Zaalinto Dutch; my thanks to her.



It seems that the change of getting green algae is big, if comparatively much nitrogen and little phosphorus is in the water. In reverse, little nitrogen c.q. a lot of phosphorus leads to a big change that you will start growing blue-green algae. The optimum seems to be at the proportion nitrogenhosphorus = 16:1. Which means a Redfield ratio of 16."




Sent from my iPad using Tapatalk

Like most of these articles, the author doesn't understand what the Redfield Ratio means. It's not the amount in the water. It's the ratio of amounts found in plankton. Some algae can become nitrate or phosphate limited in some situations, but that isn't predicted by the RR. And cyano, as HighlandReefer pointed out, certainly isn't one of them.

The only apllication for the Redfield Ratio that applies to aquarium keeping that I can see would be if you were feeding the tank phyto and wanted to calculate the ratio of nutrients you were adding to the tank. Even then, since macro-algae and other organisms use those nutrients at ratios different from plankton you will not be able to use that to predict anything about what that will do to the levels in the tank.

[disc1]

Moreover, the Redfield Ratio speaks of total elemental C, N, and P, not just nitrate and phosphate. It also includes all the other organic forms that you can't test for.