The Redfield Ratio
- Thread starter sabbath
- Start date
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.
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.
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.
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
Team RC
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
= 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.
Redfield Ratio: C:N
= 106:16:1The 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.
Last edited:
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
Premium Member
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.
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.
HighlandReefer
Team RC
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.
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.
Last edited:
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.
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
Team RC
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
Member
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
(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...............................
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
(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
-RT * ln(k)
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.
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.
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.
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
Member
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/zoetwater/calculators/redfield.html
http://buddendo.home.xs4all.nl/aquarium/redfield_eng.htm
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/zoetwater/calculators/redfield.html
http://buddendo.home.xs4all.nl/aquarium/redfield_eng.htm
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
Member
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.............
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
-RT * ln(k)
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.
Similar threads
