P&N Ratios Balancing the Equation

[sixty_reefer]

How would you use knowledge of the C N P ratio? I have a hard time seeing an application.

we already use the knowledge of C N P on carbon dosing, increasing C to decrease N and P. The more C is added the more N and P will be Removed/consumed by bacteria. This works on a ratio although we just use a dash here and there to achieve the results we want at the moment. So as we use carbon dosing to fix ratios on bacteria populations we can also understand the ratio to fix limitation on N or on P.

Knowing organic C doesn't say anything about whether that organic material is easily metabolized or not.

It doesn’t, we can’t only look at one corner of the picture, we need to look as a full and have the 3 in mind.

 

[jda]

I also never found a ratio to be of any good. Just don't worry about it.

I grow macro as an export - chaeto now but others at many times in the past. I see a slight slowdown if the N gets over 3-5 and then a significant one if it every got over 15-20. I never let N get high enough to stop stop growing. IME, your ATS will pick back up if you get the N down. This happens with P too. The macro will grow the fastest with trace levels of N and P that are present, but very low. All that I need to add is iron.

Coralline also slows down the higher that the N and P gets.

 

[sixty_reefer]

I also never found a ratio to be of any good. Just don't worry about it.

I grow macro as an export - chaeto now but others at many times in the past. I see a slight slowdown if the N gets over 3-5 and then a significant one if it every got over 15-20. I never let N get high enough to stop stop growing. IME, your ATS will pick back up if you get the N down. This happens with P too. The macro will grow the fastest with trace levels of N and P that are present, but very low. All that I need to add is iron.

Coralline also slows down the higher that the N and P gets.

I think you talking about parameters, it gets confusing wend the N (nitrogen) abbreviation is used to describe a parameter no3 (Nitrate). Parameters are not Ratios. Although you can use ratios to balance parameters.

The Parameters of a closed system are determined by the amount of Carbon, Nitrogen and phosphorus available, if one or more of the three is limited this will affect the parameters of a closed system. On the other hand if one or two are in abundance this will affect parameters also.

If the ratio of carbon, nitrogen and phosphorus are in balance than the parameters in a closed system should have stable continuous readings. ( whatever the parameters levels chosen are )

edit: Ratios would be easier to determine in a closed system without macro algae’s as this would reduce a large variable as the Transformation of C N and P varies a lot depending the size of the algae bed, light, type of algae etc…

 

[jda]

I get all of this. I am saying that it does not matter, at least to most. I don't have a way to measure carbon or available nitrogen (I am in the camp that nitrate is not a good source of nitrogen for my true coral) and I can only measure phosphorus with a Hannah, which is OK. If I cannot measure it well, at least in forms that are useful, then I don't care about it.

 

[Dan_P]

If this ratios were widely known we could have less issues balancing our tank regarding of parameter levels chosen to run the system.

Could you clarify the purpose of “balancing”. I seem to have lost the plot.

 

[sixty_reefer]

Could you clarify the purpose of “balancing”. I seem to have lost the plot.

wend I wrote balance I mean, raising and lowering parameters to a personal desired level of po4 and no3 and keep them stable/constant

 

[sixty_reefer]

I get all of this. I am saying that it does not matter, at least to most. I don't have a way to measure carbon or available nitrogen (I am in the camp that nitrate is not a good source of nitrogen for my true coral) and I can only measure phosphorus with a Hannah, which is OK. If I cannot measure it well, at least in forms that are useful, then I don't care about it.

No we can’t although we can use readings of no3 and po4 to understand we’re there are limited or abundance of C N and P giving us a vague idea of what’s happening in the tank. Triton actually do a test to measure carbon called triton N-Doc that will measure carbon I believe it’s not popular as it’s not well understood how it works.

 

[Dan_P]

wend I wrote balance I mean, raising and lowering parameters to a personal desired level of po4 and no3 and keep them stable/constant

Got it, thanks.

 

[Randy Holmes-Farley Verified Community Expert]

we already use the knowledge of C N P on carbon dosing, increasing C to decrease N and P. The more C is added the more N and P will be Removed/consumed by bacteria. This works on a ratio although we just use a dash here and there to achieve the results we want at the moment. So as we use carbon dosing to fix ratios on bacteria populations we can also understand the ratio to fix limitation on N or on P.

It doesn’t, we can’t only look at one corner of the picture, we need to look as a full and have the 3 in mind.

IMO, the absolute values are far more useful than ratios in any context that I am aware of.

 

[Randy Holmes-Farley Verified Community Expert]

If the ratio of carbon, nitrogen and phosphorus are in balance than the parameters in a closed system should have stable continuous readings. ( whatever the parameters levels chosen are )

Not sure why a balanced ratio (whatever that means) is any more stable than an unbalanced one.

I assume 0 phosphate, 0 carbon and 10,000 ppm nitrate is not balanced, but it would be rather stable. lol

 

[sixty_reefer]

Not sure why a balanced ratio (whatever that means) is any more stable than an unbalanced one.

I assume 0 phosphate, 0 carbon and 10,000 ppm nitrate is not balanced, but it would be rather stable. lol

I’m not judging although I’d assume you would be aware of nutrient limitations

 

[Randy Holmes-Farley Verified Community Expert]

I’m not judging although I’d assume you would be aware of nutrient limitations

Of course, which is one big reason why absolute values are more useful than ratios, which are nearly impossible to interpret on their own.

If I provide any ratio of C:N: P you cannot ever say with certainty what is limiting without knowing the actual values. Suppose it is the exact Redfield ratio found in the ocean. What is limiting?

If you need to know the actual values to answer the question, why look at ratios in the first place?

 

[sixty_reefer]

Of course, which is one big reason why absolute values are more useful than ratios, which are nearly impossible to interpret on their own.

If I provide any ratio of C:N: P you cannot ever say with certainty what is limiting without knowing the actual values. Suppose it is the exact Redfield ratio found in the ocean. What is limiting?

If you need to know the actual values to answer the question, why look at ratios in the first place?

That’s the thing Redfield on its own it’s useless for the average aquarists, we need to use the knowledge of redfield in nutrient limitations and how it affects a system, that’s what we need to discuss more instead of saying that redfield in home aquaria is useless.

if no3 and po4 are stable in a closed system congratulations the ratio in that system is in balance.

Now if you come to me and said my no3 keep going down in my system?

knowledge of nutrient limitation can be applied here. If no3 is rapidly depleting in a closed system we normally just add more food or find a source of no3 to add to the tank to fix the individual ratio of that closed system. As you know some foods have a higher content of carbon than others if you were to just add a food with a higher content of carbon to try and raise no3 that would be kind of useless imo, dosing no3 in a chemical form would work but it’s not helping anyone looking for what caused that particular system to have a sudden increase in Carbon.

This is just an example many other issues related to no3 and po4 limitations or abundance can be fixed using the knowledge of the ratios and how they interact on a general overview.

hope am not making it to confusing just rushing a bit to write this

 

[Randy Holmes-Farley Verified Community Expert]

I understand nutrient limitations and also the Redfield ratio, but ratios alone are of little to no value and even absolute values do not always tell us what is limiting.

 

[sixty_reefer]

I understand nutrient limitations and also the Redfield ratio, but ratios alone are of little to no value and even absolute values do not always tell us what is limiting.

If we take mechanical filtration out of the equation they do, and we can use no3 and po4 fluctuations to determine which one is limited or in abundance for the overall consumption/transformation of a closed systems. But that’s all it can do, it can tell us which one is out of balance but it won’t give us a value.
Knowing which one is out of balance will help determine a way to bring a stability to nutrients. Or in a case of a ULN it will be beneficial to be able to import more and export more using primarily bacteria.

 

[jda]

As I said before, you cannot use any test kits, besides maybe phosphate/phosphorous to see if you are limited on the low side. Nitrate test kit does not show available nitrogen and is fools gold - if you wanted to constantly test ammonia/ammonium, then maybe. There is no good carbon test kit. Even 1-3 ppb of phosphate is not limiting, IME.

I have .1 nitrate. I am not nitrogen limited whatsoever, but I base this just on the fast growing and thriving corals.

You can use po4 and no3 test kits to see if you are climbing too high and might be high-limiting, but not on the low-limiting side.

These are no more than guides, should not ever be used in a ratio and unless you need actual no3 for something, like macroalgae or to limit dinos/cyano/diatoms, then the reading usually causes more misunderstanding than answers questions.

 

[Randy Holmes-Farley Verified Community Expert]

If we take mechanical filtration out of the equation they do, and we can use no3 and po4 fluctuations to determine which one is limited or in abundance for the overall consumption/transformation of a closed systems. But that’s all it can do, it can tell us which one is out of balance but it won’t give us a value.
Knowing which one is out of balance will help determine a way to bring a stability to nutrients. Or in a case of a ULN it will be beneficial to be able to import more and export more using primarily bacteria.

IMO, using ratios for what you propose will often fail (all low, all high, etc, but at your perfect ratios) while setting all elements at appropriate absolute values will never fail.

 

[sixty_reefer]

As I said before, you cannot use any test kits, besides maybe phosphate/phosphorous to see if you are limited on the low side. Nitrate test kit does not show available nitrogen and is fools gold - if you wanted to constantly test ammonia/ammonium, then maybe. There is no good carbon test kit. Even 1-3 ppb of phosphate is not limiting, IME.

triton offers N-Doc testing not sure how good they are but the absolute values of C N and P are not useful for the average

I have .1 nitrate. I am not nitrogen limited whatsoever, but I base this just on the fast growing and thriving corals.

No you won’t be as long as the value

You can use po4 and no3 test kits to see if you are climbing too high and might be high-limiting, but not on the low-limiting side.

Both can be used imo

These are no more than guides, should not ever be used in a ratio and unless you need actual no3 for something, like macroalgae or to limit dinos/cyano/diatoms, then the reading usually causes more misunderstanding than answers questions.

The ratio is for a overhaul ecosystem or closed system and can be used to regulate the system as a hole.

 

[sixty_reefer]

IMO, using ratios for what you propose will often fail (all low, all high, etc, but at your perfect ratios) while setting all elements at appropriate absolute values will never fail.

The perfect ratio will make the parameter stable regarding of value that they are run at.

 

[Randy Holmes-Farley Verified Community Expert]

The perfect ratio will make the parameter stable regarding of value that they are run at.

Is regarding a typo of regardless?

I cannot see how good ratios make parameters stable and bad ratios make them unstable. The ratio may be stable against consumption in the same ratio, but the values may rise and fall to unacceptable values with that same ratio.