Nutrient Balance

Discussion in 'Reef Chemistry by Randy Holmes-Farley' started by Servillius, Jan 2, 2018.

  1. Servillius

    Servillius Active Member R2R Supporter Build Thread Contributor Reef Tank 365

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    Before I start, I want to emphasize what follows is conjecture on my part offered to advance a conversation. I couldn’t really say I’m sure of anything and since I’m too lazy to refer to references, I could be plain wrong in places. I’m very interested in learning what here could be useful to future reefers and to improving it as best we can.

    I’m starting to get the feeling some sound advice is being misunderstood in a way that might cause tank problems.

    We’re hearing a lot these days about getting your nutrients too low. My concern is that people who have yet to get full control over their nutrients are taking this to mean they should be adding rather than managing.

    This lead me to thinking about just exactly how on establishes a reasonably stable equilibrium in a tank.

    The first time I thought about this I was trying to understand Zeo. ZeoStart, I’m fairly sure, is acetic acid and some nitrate compound. You’re dosing carbon and nitrate at the same time. The carbon drives down N and P and the additional N helps drive down more P. Here is where it gets interesting. Zeo is adamant you don’t need to do anything else to reduce phosphate and in practice, they’re right. Why? What if there’s not enough N? What if there’s too much? Turns out I don’t think it’s an issue. We know there’s a rough balance in uptake (Redfield, etc.). By adding more, it’s unlikely there will be too little. If there’s too much, your tank has other processes for taking up nitrogen that are underutilized in a clean tank. So your rock acts as a buffer against too much nitrogen. If Zeo is correct and the zeolite is reducing it as well, voila, stable equilibrium.

    Okay, so what if you’re not using Zeo? Let’s say you’re using chaeto instead? You crank up the chaeto growth and drive your nutrients down. Presumably when they get low enough one or the other will remain in excess. So you have to dose, right? Not so (let’s leave aside whether you need to dose for coral health, I’m just talking equilibrium here). You either end up with nitrate being too low or nitrate being too high (phosphate being too low). But your tank comes ready made to deal with either. If there isn’t enough phosphate, excess nitrate gets broken down in the rock, etc. if there isn’t enough nitrate, you get something that can subsist on organic phosphate. Cyano is a nitrogen fixing little bug. Far from being a pest, it’s actually working to bring your tank into equilibrium. If you’re pushing down the overall nutrient level sufficiently, it will do it’s job then fade away.

    Based on this you could predict the red slime phase tanks go through, the reason established tanks better tolorate high nutrients, as well as a lot of the other stuff we regularly experience. You should also be able to predict the amount of each nutrient in solution in a well established tank based mainly on the knowledge your removal exceeds your input and on the quantity you add.

    My point, for those insane enough to get to it, is that I think the correct advice is to eliminate your nutrients, then increase them a bit. Advising people to target a number leads folks who have not yet established an equilibrium to start chasing their test kits. It can work, but the system is unstable.

    An alternative to raising them once you get close to 0 is to run nutrient removal intermittently. As long as you’re running it enough to get everything out over the course of the day, the off cycles will result in plenty of opertunity for corals to outcompete your filtration while still maintaining a closer to natural environment (also interestingly consistent with Zeo directions).
     
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  2. Travis Stewart

    Travis Stewart Valuable Member Reef Tank 365

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    Following
     
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  3. Steved350

    Steved350 Active Member

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    Very interesting. Following
     
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  4. Randy Holmes-Farley

    Randy Holmes-Farley Reef Chemist Staff Member Team R2R R2R Supporter R2R Excellence Award Article Contributor Expert Contributor

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    While the idea of nitrogen fixing cyano theoretically solves the issue of excess phospahte, in practice, many reefers are permanently left with an excess of phosphate. That may or may not be a problem, but it does not seem to go away on its own.

    There really does not appear to be a good ongoing way for most reef tanks to naturally deplete a substantial excess of phosphate if nitrogen sources run out (say, by tissue growth or denitrification), hence why so many people use GFO or other phosphate-specific export methods.
     
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  5. Travis Stewart

    Travis Stewart Valuable Member Reef Tank 365

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    Hey randy, what if you have got the issue excess issue under control, yet you want to balance the levels to be higher than a ulns and to keep corals eating.
     
  6. Randy Holmes-Farley

    Randy Holmes-Farley Reef Chemist Staff Member Team R2R R2R Supporter R2R Excellence Award Article Contributor Expert Contributor

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    IMO, it is fine to dose either nitrate, phosphate, or both. :)
     
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  7. Brew12

    Brew12 Electrical Gru Staff Member Team R2R R2R Supporter R2R Excellence Award Build Thread Contributor Reef Tank 365 Article Contributor Partner Member 2018 Partner Member 2019 North Alabama Reef Club

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    I find these topics fascinating and have read many scientific studies on the topic. I only wish I could find more research on it that related directly to reef tanks. I guess the hobby is still too small. :(

    I do want to caution you against one thing that I feel really trips people up. When we look at uptake we refer to N and P. We test for NO3 and PO4. These are in not equivalent. There are other sources of N and P, both organic and inorganic, that we do not test for. As an example, NH3/NH4 can be directly taken up by algae, corals, and some bacteria. It isn't in the water long enough for us to register it on a test. Yet, this is a major source of N in our tanks.

    Just something to keep in mind.
     
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  8. Randy Holmes-Farley

    Randy Holmes-Farley Reef Chemist Staff Member Team R2R R2R Supporter R2R Excellence Award Article Contributor Expert Contributor

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    That's one of the things I'd like to know more about. Does a typical coral get more N from NH3 or NO3- in an ordinary reef tank?
     
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  9. Brew12

    Brew12 Electrical Gru Staff Member Team R2R R2R Supporter R2R Excellence Award Build Thread Contributor Reef Tank 365 Article Contributor Partner Member 2018 Partner Member 2019 North Alabama Reef Club

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    I'm curious about this too.

    I would really like to know the impact of macro algae on NH4/NO3. It seems tanks with a lot of algae often read 0ppm NO3. I would like to know how much of this is caused by the algae consuming NO3 and how much is from it consuming NH4 directly so less/no NO3 is produced by nitrifying bacteria.

    Macro algae has become my favorite method of ammonia control in my QT system. I never see any NH3/NH4 or any NO3. Grow it in the sump, use it in the QT, toss it in the garbage. Free filtration.
     
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  10. Gareth elliott

    Gareth elliott Valuable Member R2R Supporter R2R Excellence Award Build Thread Contributor NJRC Member

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    Following along. Id also like to know if potassium would have a part in this ratio as with terrestrial plants.

    If this would would true for zooxantellae but at a different ratio to N an P.
     
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  11. Servillius

    Servillius Active Member R2R Supporter Build Thread Contributor Reef Tank 365

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    You are of course correct. When you get close to equilibrium however, there may be enough mechanisms to keep a small excess of phosphate in line. Probably why some tanks are able to stay stable without dealing with an excess (along with reserve nitrogen removal).

    More to the point, even if the answer is that in a well managed tank a little extra nitrogen helps with excess phosphate, or that GFO does, or whatever, it still suggests It would be easier to get a tank in balance by driving down nutrient and dosing when that effort is complete and successful rather than dosing based on current test results.

    Put another way in a six month old tank covered in algae if their nitrate seems too low relative to their phosphate is it better to dose nitrate or to focus on nutrient reduction?

    I’m not sure everyone is understanding that order of events.
     
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  12. Servillius

    Servillius Active Member R2R Supporter Build Thread Contributor Reef Tank 365

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    And significant phosphate?
     
  13. Servillius

    Servillius Active Member R2R Supporter Build Thread Contributor Reef Tank 365

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    We could set up a nano, observe a coral for a bit once everything is healthy, then aggressively strip ammonia and replace the nitrogen with potassium nitrate. Anyone willing to run the experiment?
     
  14. Servillius

    Servillius Active Member R2R Supporter Build Thread Contributor Reef Tank 365

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    You know, when the first few responses are just people following, you start feeling like the schmuck that volunteered to go 10 rounds with the Russian Giant at the carnival and just realized you’re really drunk and he’s a lot bigger than you thought.
     
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  15. Brew12

    Brew12 Electrical Gru Staff Member Team R2R R2R Supporter R2R Excellence Award Build Thread Contributor Reef Tank 365 Article Contributor Partner Member 2018 Partner Member 2019 North Alabama Reef Club

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    Unfortunately, I have never tested my QT for phosphate. And even though it is up and running right now I am running Chloroquine Phosphate as a treatment so I doubt I can get accurate results. :confused:
     
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  16. Gareth elliott

    Gareth elliott Valuable Member R2R Supporter R2R Excellence Award Build Thread Contributor NJRC Member

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    Maybe could test with a ph adaptable marine algae.

    Could use a lowered ph containers of water to test the uptake rate ammonia vs nitrate.

    Use co2 impregnation to lower ph to below where ammonium not ammonia is formed.

    Dose standardized amounts of nutrients in varying ratios in the different containers. Test for leftover amounts at standardized intervals.

    Set control containers to ph of 8.14 for each ratio tested.

    I know in growth tests on citrus trees the optimum ratio of no3/no4 is 80/20. How this would relate to marine life no idea lol.
     
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  17. Servillius

    Servillius Active Member R2R Supporter Build Thread Contributor Reef Tank 365

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    At the very least it’s worth remembering there’s a lot of folks out there very motivated to study plants that we can piggyback on.
     
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  18. Gareth elliott

    Gareth elliott Valuable Member R2R Supporter R2R Excellence Award Build Thread Contributor NJRC Member

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    Plants had a helping hand with both carl linnaeus and charles darwin being botanists.
    A lot of the beginnings of species studies started on plants. Darwin in particular used orchids to study adaptation.
     
  19. Randy Holmes-Farley

    Randy Holmes-Farley Reef Chemist Staff Member Team R2R R2R Supporter R2R Excellence Award Article Contributor Expert Contributor

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    There is a large amount of potassium naturally in seawater. You may need to monitor it, but it never depleted in my tank over 20 years. :)
     
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  20. Nano sapiens

    Nano sapiens Well-Known Member R2R Supporter Build Thread Contributor

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    I believe that part of the issue is that a stable equilibrium (a reef is currently described as in a state of dynamic equilibrium) is not easily recognized by a novice reef aquarist, especially. As a result, there is a tendency to 'err on the side of caution' and aggressively export nutrients often to the detriment of the system as a whole, especially if imports are not sufficient to properly sustain the organisms. IMO, the 'art' in reef keeping is in determining/maintaining an acceptable balance between the two import and export extremes.

    For the last 9-1/2 years I've been running a small 12g 'mixed reef' nano tank partially for enjoyment, but also as an experiment to see if a system this small could self-stabilize without the use of chemical or mechanical filtration . Without going into boring details, for the last 7 years NO3 has been under 1 ppm (often less) and PO4 has read '0' (Salifert, Elos). A Triton test determined that both inorganic and organic levels of phosphate are around half of the recommended levels for a reef tank. Yet, the corals are healthy, colorful and growing. I do maintain a good fish stocking (currently six 2" average size Gobies & Blennies), so my assumption here is that ammonium excreted by them, and the phosphate from 2x/day feedings, is quickly utilized by the good number of mature coral/false corals present...which ultimately results in low NO3 and phosphate in the water column.

    From what I have observed over the many years, there are multiple ways to run a reef system and that a natural system is inherently capable of reaching a state of equilibrium given time...if external disruptions are not excessive.

    Ralph.
     
    Last edited: Jan 4, 2018
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