Beating redfields ratio??? (nitrate reduction)

Discussion in 'Chemical Filtration / Low Nutrient Systems - LNS' started by Visser, 15 Oct 2012.

  1. Visser

    Visser MASA Contributor

    Joined:
    21 Nov 2011
    Posts:
    2,670
    Likes Received:
    45
    Location:
    Willows,Pretoria /Brits
    Recently, there has been a lot of talk on MASA about the redfields ratio (ratio of nitrogen, phosphorus & carbon in planctonic creatures).
    Ive always followed redfield discussions out of curiosity, but only this week i finally got a glimpse of what its all about (or at least a part of it).
    Ive always been a fan of low nutrient systems & always tried to keep my tank's nutrients as low as possible for 2 reasons:
    1. algae control
    2. Sps coral colors

    Ever since i started my latest tank, my phosphates has always been very low (+-0.01) but ive always had some nitrates (around 2-4ppm).
    I could never understand why i cant get my nitrates below 1ppm...
    About 3 weeks ago, i added Orca nitra-guard biocubes (fantastic product) to my tank.
    The effect was that my nitrates dropped from 4ppm to 2ppm in one week & phosphates from 0.01-undetectable even on a professional test kit.

    My problem is this... my nitrates seem to have stabilized at 2ppm even with the biocubes in my tank & doesn't seem to get lower than that no matter what!!!

    My question:
    Can it be that the absence of phosphorus (phosphates) in my tank is prohibiting the bacteria's ability to absorb (convert) any more nitrates because of the imbalance in redfields ratio & if so,
    1. How can i overcome this barrier in my nitrate level?
    2. Is this a common finding in low nutrient systems?
    3. Do i need to increase the phosphates to balance the ratio?(preferably dont want to try this...)
    4. Is it possible with the newer Nitra-guard titanium to overcome similar redfield ratio problems?

    Any advice would be greatly appreciated!!!
    Thanks guys!:)
     
  2. AdS Guest




    to hide all adverts.
  3. irie ivan

    irie ivan MASA Contributor

    Joined:
    6 May 2007
    Posts:
    3,149
    Likes Received:
    171
    Location:
    Bracken
    Very Likely...

    Add a bit of Nitra Guard Titanium Bio Cubes

    Don't increase po4

    Your last Q, answered above.

    Your problem is less common than NO3 being the limiting factor to PO4 assimilation / removal.\, consider yourself lucky!

    Another consideration is the potential of nitrate "factory" in your system. A high oxygenated area, whereby our traditional Bacteria strains convert Nitrite into ntrates. The cubes should cope with the nitrate due to food inputs, as there is a decent measure of PO4 as a non optional extra when we feed.
    My suspicion is that the carbon infused subtrate (cubes) should therefor handle the imbalance caused by an in-tank NO3 factory...... Dependant on the quantity..... Its all about balance....
     
  4. dallasg

    dallasg Moderator MASA Contributor

    Joined:
    14 Dec 2008
    Posts:
    16,769
    Likes Received:
    582
    Location:
    Sandton
    no need to answer more, nicely put
     
  5. Visser

    Visser Thread Starter MASA Contributor

    Joined:
    21 Nov 2011
    Posts:
    2,670
    Likes Received:
    45
    Location:
    Willows,Pretoria /Brits
    Thanks @irie ivan, that answers my question 100%!!!

    I have always been extremely lucky with low phosphates which i believe is partly achieved by my very strict feeding ideologies...

    The "nitrate factory" makes some sense (& ive always suspected it) is very possible as i have extremely porous liverock in my system & no DSB or any other low oxygen area in my tanks... (i kind of like it that way... but the side effect is higher nitrates)

    As for the Biocubes titanium... Where can i get hold of them? I havent seen any in the petshops here in gauteng?

    Thanks again
     
    Last edited by a moderator: 26 Nov 2015
  6. ChrisRaubs

    ChrisRaubs

    Joined:
    30 Jun 2012
    Posts:
    892
    Likes Received:
    6
    Location:
    Pretoria
    Hey @Visser you can give @bryan from jungle aquatics a shout. Almost sure he stocks them and free delivery to parts of the country...
     
    Last edited by a moderator: 26 Nov 2015
  7. Visser

    Visser Thread Starter MASA Contributor

    Joined:
    21 Nov 2011
    Posts:
    2,670
    Likes Received:
    45
    Location:
    Willows,Pretoria /Brits
    Thanks for the headsup @ChrisRaubs, i just got confirmation from jungle aquatics that the nitra-guard titanium will only be available towards the end of november, so i guess i will have to wait for a couple of weeks...

    @irie ivan, do you think that large waterchanges will work to bring my nitrates down to a level closer to redfield ratio to assist my nitra-guard in nitrate reduction?
     
    Last edited by a moderator: 26 Nov 2015
  8. Visser

    Visser Thread Starter MASA Contributor

    Joined:
    21 Nov 2011
    Posts:
    2,670
    Likes Received:
    45
    Location:
    Willows,Pretoria /Brits
    Just a quick update on this thread...
    As suggested by @irie ivan, i purchased a 500ml tub of the new orca nitra-guard titanium & added it to my tank...
    Within 2-3 weeks it was able to reduce my nitrates from 3ppm to undetectable which is amazing as it is the first biological nitrate reduction method that is not dependant on phosphates in the system!!!
    I did a quick review of the product to document my results...

    http://www.marineaquariumsa.com/showthread.php?t=39292

    I would definitely recommend the nitra-guard titanium to anyone with similar problems as i had!!!
     
    Last edited by a moderator: 26 Nov 2015
  9. Dillan

    Dillan

    Joined:
    10 May 2012
    Posts:
    785
    Likes Received:
    3
    Location:
    Bloemfontein/Cannon Rocks
  10. LCornelius

    LCornelius Moderator

    Joined:
    5 Mar 2009
    Posts:
    5,460
    Likes Received:
    124
    Location:
    Durbanville (CPT)
    Very nice thread @Visser!
    Great info and input from all!

    Not to hi-jack, but would running a phos reactor and titanium bio cubes fight each other, or would the reactor be a complete waist? @irie ivan
     
    Last edited by a moderator: 26 Nov 2015
  11. Nemos Janitor

    Nemos Janitor

    Joined:
    7 Feb 2009
    Posts:
    8,384
    Likes Received:
    286
    Location:
    Joe's Mountain
    I believe that many are confused with the working of the redfield stoichiometry. The stoichiometry refers to C:N:p or C:Si:N:P: which ever "version" one wants to consider.

    "C" refers to total carbons. "Si" to total silicates, "N" to total nitrogen and "P" to total phosphorus.

    I only see reference to NO3 and PO4 that is accounted for in testing

    What of the other/rest of the "P" and "N". ?? and "Si"?

    Is there masking???
     
    Last edited: 20 Nov 2012
  12. Visser

    Visser Thread Starter MASA Contributor

    Joined:
    21 Nov 2011
    Posts:
    2,670
    Likes Received:
    45
    Location:
    Willows,Pretoria /Brits
    Thanks @LCornelius,
    You're more than welcome to highjack this thread with any questions!
    Any phosphate reducing media (eg orca phospha-guard, phosban & seachem phosguard) work perfectly together as the titanium removes your nitrates (without requiring/reducing phosphates) while the phophate media will make sure your phosphates stay low...
    A perfect combination if you ask me!!! & a very easy way to achieve an ULNS without spending a fortune on reactors & equipment!!!
     
    Last edited by a moderator: 26 Nov 2015
  13. irie ivan

    irie ivan MASA Contributor

    Joined:
    6 May 2007
    Posts:
    3,149
    Likes Received:
    171
    Location:
    Bracken
    At the old man: what is important to remember is that this whole redfield thing is really just a "guideline" which we have jumped on due to lack of hobbyist based literature on exactly whats happening in our systems in terms of CNP ratios. The redfield stoichiometry thing is based on averages whilst studying phytoplankton, not yeast or bac. In saying that, i am sure mr Redfields samples contained some yeast and bacterioplancton. Their individual and combined effects on his results will remain an unknown. Also, their actual ratio will remain a huge unknown, until killer whale stops developing cutting edge tiys and gets down to doing research and publishing it....,
    For now, we know there is a ratio, exactly what it involved, really not sure, but we can safely assume CNP are the chief players, but i am sure Si also quite involved...
    If however this is the case, we might have a limiting factor due to gfh use. Does not seem to have manifest itself yet, but then again, how many ofbus measure it....
    Once diatoms and gfo has stripped it out, we seem to forget all anout it......

    Perhaps the glass in our tanks are dessolving at a rate to support the ratio, LOL.

    Really wanna get into this discussion again, but just pressed for time...
     
  14. Nemos Janitor

    Nemos Janitor

    Joined:
    7 Feb 2009
    Posts:
    8,384
    Likes Received:
    286
    Location:
    Joe's Mountain
    Me too :p

    However the subject must not be over simplified as there are many considerations other than NO3 & PO4. that can and must be considered, over time.

    Feeding of foods? Are the plankton foods REDFIELD applyant. :biggrin:
     
  15. Visser

    Visser Thread Starter MASA Contributor

    Joined:
    21 Nov 2011
    Posts:
    2,670
    Likes Received:
    45
    Location:
    Willows,Pretoria /Brits
    Silica & carbon in the redfield ratio

    I was hoping that someone would ask that question... I must say, it is a very complicated subject in any marine biology article that I have read, & have never heard of any scientist that has fully discovered the purpose/reasons why this ratio exists...
    So, to give you an answer that is 100% scientifically correct, would be nearly impossible but i will do my best from what I have researched.

    The only logical reasoning I have been able to gather from scientific articles is that this ratio creates a chemical balance where living aquatic creatures can absorb nutrients & minerals in their natural environments which fuels their growth & reproduction rates. Thus it can be assumed that planktonic blooms has a lot to do with the chemical balances & availability of specific element that is required by all planktonic creatures to thrive…

    To get back to the elements found in the redfield ratio, i should start with silica, as it is the one that is least concerning to aquarists..
    Silica
    As most experienced reefers probably know by now, the Redfield’s ratio (or Redfield-Brzezinski nutrient ratio. Which is what the ratio is called when silica is taken into consideration) is a constant ratio where Carbon, silica, nitrogen & phosphates is established in a constant ratio within living biomasses found in aquatic environments.
    This ratio has been established to be constant at
    C : Si : N : P = 106 : 15 : 16 : 1
    Silica in marine aquariums is mostly not considered a “threat” in keeping a successful aquarium as it can fairly easily be removed from any aquarium (not intentionally) by means of Granular ferric oxide media (the media used to remove phosphates from aquaria) & is also quickly converted by marine sponges & bivalves, which can be found on almost any piece of live rock. It is also removed to some extent by skimming out the bacteria that has absorbed these silicates.
    The other reason why it isn’t such a problem, is that it isn’t very dissolvable (it tends to stay bound in its chemical formula) & doesn’t get biologically broken down into its base element, which means that, unlike nitrogen (which is a gas), silica is a solid & takes a lot more energy to accomplish binding of silica to another element. Thus, the quantized energy level of most silica based chemicals are quite low if I remember correctly & is more difficult to break down into other chemical combinations…
    The only real nuisance from excess silica in the aquarium is diatoms. Diatoms use silicic acid & converts it to biogenetic silica to use as the skin forming agent for their frustules/cellular skins & therefore, when there is too much silica in a system… There will be lots of diatoms to follow!
    The only other creatures that use silica is bivalves & sponges, & uses the silica in the growth of its “flesh” & skin.
    There is a lot of other info on silica that I haven’t even touched here, but I will be typing for the rest of the day to even begin to sum it up!
    CARBON
    Carbon is an amazing element by itself. It has the ability to be combined in endless amounts of molecular bindings.
    It is very difficult to understand the effect of carbon in the Redfield ratio as it is extremely complex to measure as it is found in in endless molecular combinations, & to make it more complex, the carbon that is utilized in the Redfield ratio is only organic carbon, which means that the organic & inorganic carbons need to be separated & then the pure organic carbon needs to be measured to establish the true carbon value in any organic biomass.
    For any normal aquarists, this is an impossible task to accomplish as there is no “off the shelf” test kits available to measure this…
    All that I can say about carbon (& I think most reefers know this by now) is that it is a very effective food source for bacteria & plays a major role in the growth / reproduction of these bacteria & nutrient uptake by bacterial biomasses in the water column as is evident for example, when too much alcohol is added at once to an aquarium, the bacteria will multiply at such a rate that they will cloud the water very quickly & in the same process, the nitrate & phosphate levels will drop as the bacteria needs to absorb the C : N : P in rational amounts.
    The carbon that is absorbed gets converted into Carbon dioxide & hydrogen gas, the nitrates gets converted into nitrogen & oxygen and the phosphates gets absorbed into the cells of the bacteria & when the bacteria dies, the phosphates gets released back into the water.
    This is why phosphates can become a problem in aquariums… They stays dissolved in the water column until it is either skimmed out (while absorbed in the bacteria) or by means of GFO.
    So, to sum up carbon: It is the main food source for planktonic creatures & they require carbon to grow & in return they absorb nitrates & phosphates. Fortunately, carbon isn’t bad for aquariums at amounts commonly found in aquariums & is easily removed from the water either by skimmers (to remove Dissolved organic carbons) or when converted by bacteria into carbon dioxide gas.

    TOTAL C : SI : N : P
    Regarding your question about the total measurable amount of each element found in the ratio, it is a bit easier to explain.
    The Phosphates & silicates within the aquarium are always found in very stable compounds when in its chemical combination & is therefore assumed to have a fixed molecular count within its compound.
    For example, phosphorus is almost always found as a phosphate within the aquarium & therefore it is only required to measure the phosphates in the water & then divide that into the molecular masses of each of the elements in the formula & you will have your true phosphorus molecular mass to compare with the other elements in the ratio.
    Nitrogen on the other hand may seem a lot harder to measure than phosphorus & silica’s as they appear in a lot more chemical combinations for example: ammonia, nitrites, nitrates & finally nitrogen (The nitrogen cycle as we all know it). But is actually quite easy to measure as the ammonia & nitrites gets converted very quickly into nitrogen within an established aquarium & therefore it is only required to measure nitrates & then follow the same procedure that I explained above to find the molecular weight of the nitrogen within the formula.
    The pure nitrogen gas is usually not measurable as it escapes the water & into the atmosphere almost instantly.
    Therefore we can say that there is a direct relationship between the C : SI : P : N & C : SI : PO4 : NO3 ratio within our aquariums & enables us to directly convert the chemical compounds into the molecular mass of each element.

    Thus, to get back to your question around the two elements of the Redfield-Brzezinski nutrient ratio that we don’t mention in aquarium articles namely Silica & Carbon. The reason is because that they are easily eliminated from the marine aquariums or isn’t an obstruction in successful aquarium keeping & is therefore not considered as critical elements to control in our hobby.
    Hope this could answer your question to a certain extend…
    Please forgive me if I used incorrect scientific terminology as English is definitely not my home language & I most certainly don’t know all the correct English chemistry names for everything, lol!!!
    If there is anything that I explained incorrectly, feel free to correct me as this is my own understanding of the redfield ratio that I have extensively researched over a couple of years to get to this conclusion.
    @carlosdeandrade, @irie ivan, @Nemos Janitor, @dallasg
     
    Last edited by a moderator: 26 Nov 2015
    erratiC likes this.
  16. labworx

    labworx

    Joined:
    17 Nov 2011
    Posts:
    74
    Likes Received:
    0
    Location:
    centurion
    Thank you @Visser. :thumbup:
    It so much easier when someone explains things in english! All that scientific babble makes my brain go numb . . . :banghead:
     
    Last edited: 21 Nov 2012
  17. Visser

    Visser Thread Starter MASA Contributor

    Joined:
    21 Nov 2011
    Posts:
    2,670
    Likes Received:
    45
    Location:
    Willows,Pretoria /Brits
    Last edited by a moderator: 26 Nov 2015
  18. dallasg

    dallasg Moderator MASA Contributor

    Joined:
    14 Dec 2008
    Posts:
    16,769
    Likes Received:
    582
    Location:
    Sandton
    Visser, thats a great reply, why dont you make it an article
     
  19. Visser

    Visser Thread Starter MASA Contributor

    Joined:
    21 Nov 2011
    Posts:
    2,670
    Likes Received:
    45
    Location:
    Willows,Pretoria /Brits
    Thanks Dallasg, that's a good idea...
    Will do a full article on redfield ratio in a week or two...
     
  20. Nemos Janitor

    Nemos Janitor

    Joined:
    7 Feb 2009
    Posts:
    8,384
    Likes Received:
    286
    Location:
    Joe's Mountain
    @Visser, Thank you for the explanation. Here is an interesting article on Si. ( @RiaanP it discusses Si in play sand) Whilst this article does not specifically go into the Redfield Stoichiometry it does make reference to Si becoming limiting in N and P reduction. We know that Si is required and present in plankton. From this one could assume that the use of a GFO to remove PO4 could also deplete Si causing Si to become limiting.

    http://www.advancedaquarist.com/2003/1/aafeature1
     
    Last edited by a moderator: 26 Nov 2015
  21. carlosdeandrade

    carlosdeandrade

    Joined:
    24 Dec 2010
    Posts:
    8,230
    Likes Received:
    228
    Location:
    North Riding, Jozi
Recent Posts

Loading...
Similar Threads - Beating redfields ratio Forum Date
Busy Beating Bryopsis Nuisance Algae 17 Jun 2007