Organic vs Inorganic N and P

[LadyTang2]

When we talk about sources of N and P in reekfeeping

Do either organic or inorganic N have advantages over the other?

Do either organic or inorganic P have advantages over the other?

I'm less interested in a definition but more how to think about these and what the difference is when supplying or removing the organic or inorganic forms.

 

[Scrubber_steve]

In simple terms, organic N & P break down into inorganic N & P.
You could think of the organic form as food & the inorganic as waste.
Excess organic compounds are removed via skimming & GAC, for example.
Excess of the inorganic form must be removed & this is achieved via nitrifying & de-nitrifying bacteria.
The inorganic form is also necessary for photosynthesising organisms such as coral & algae, being assimilated into their tissue.

 

[LadyTang2]

I see the organic form is more for food, is the inorganic almost never food? What methods of filtration can remove inorganic N & P other than denitrifying bacteria?

Calcium nitrate is inorganic N I believe, companies sell this to raise N for corals, so it is being used as food so this doesnt quite fit your description but maybe you were giving me a more broad generalization? That can be helpful dont get me wrong!

 

[Scrubber_steve]

I see the organic form is more for food, is the inorganic almost never food? What methods of filtration can remove inorganic N & P other than denitrifying bacteria?

Inorganic is food in terms of photosynthesis. It's assimilated into the tissue of the photosynthesising organism.
So growing algae is a great method to remove the excess inorganic nutrients from the water.

Algae scrubber - refugium

 

[LadyTang2]

Why doesnt a refugium remove organic

Why doesnt a skimmer remove inorganic

Is this related to polarity/hydrophyllia/phobia?

 

[Phildago]

Why doesnt a refugium remove organic

Why doesnt a skimmer remove inorganic

Is this related to polarity/hydrophyllia/phobia?

Because organic phosphorus and nitrogen is too large to utilize easily. It's bound to carbons and is fairly stable, so it would need to be broken down into inorganic to then be utilized.

Generally organic phosphorous would be phospholipids ie. Fats

And organic nitrogen would be amino acids. Ie. Proteins or smaller fragments of proteins.

 

[Phildago]

Here's an easy way to think of it. Organic n and p is like a cheese burger. Plenty of fat and protein. The inorganic n and p is like cow dung fertilizer.

 

[Dan_P]

When we talk about sources of N and P in reekfeeping

Do either organic or inorganic N have advantages over the other?

Do either organic or inorganic P have advantages over the other?

I'm less interested in a definition but more how to think about these and what the difference is when supplying or removing the organic or inorganic forms.

Great question, and a complicated one.

Is your main interest in how much to feed or what to feed a reef system? Are you trying to decide what nutrient export systems to buy, like skimmer versus GAC vs carbon dosing?

 

[Randy Holmes-Farley Verified Community Expert]

When we talk about sources of N and P in reekfeeping

Do either organic or inorganic N have advantages over the other?

Do either organic or inorganic P have advantages over the other?

I'm less interested in a definition but more how to think about these and what the difference is when supplying or removing the organic or inorganic forms.

Advantage is in the eye of the beholder. What do you want to consume it and what else would the organisms use organics for.

Bacteria may benefit most from organic firms relative to inorganic firms since they are set up to also get energy from it.

some forms of both organic and inorganic N and P will be toxic, so don’t generalize too much.

 

[LadyTang2]

Great question, and a complicated one.

Is your main interest in how much to feed or what to feed a reef system? Are you trying to decide what nutrient export systems to buy, like skimmer versus GAC vs carbon dosing?

Is this right...
Organic carbon is used in carbon dosing, denitrifying bacteria eat the Org carbon but this also makes them hungrier for inorganic N, not organic N (per steve above)? The main benefit to this is now these larger bacteria can be removed via filtration taking the N and P with them. So without the filtration later carbon dosing wont work?

Corals need N and P, do they eat organic or inorganic N and P? Do they consume the bacteria which contain the N and P? I would think the bacteria would be larger than the individual org or inorg N and P compounds themselves.

Do fuges, socks, skimmer, gac all remove organic N and P but not inorganic, is this because their only large enough to remove when they are inside larger bacteria?

 

[LadyTang2]

Advantage is in the eye of the beholder. What do you want to consume it and what else would the organisms use organics for.

Bacteria may benefit most from organic firms relative to inorganic firms since they are set up to also get energy from it.

some forms of both organic and inorganic N and P will be toxic, so don’t generalize too much.

Is this right...
Organic carbon is used in carbon dosing, denitrifying bacteria eat the Org carbon but this also makes them hungrier for inorganic N, not organic N (per steve above)? The main benefit to this is now these larger bacteria can be removed via filtration taking the N and P with them. So without the filtration later carbon dosing wont work?

Corals need N and P, do they eat organic or inorganic N and P? Do they consume the bacteria which contain the N and P? I would think the bacteria would be larger than the individual org or inorg N and P compounds themselves.

Do fuges, socks, skimmer, gac all remove organic N and P but not inorganic, is this because their only large enough to remove when they are inside larger bacteria?

I see Calcium nitrate products being sold to increase N, this is inorganic N, how is this used by the corals (ties into above question) and do you like Ca nitrate better than na nitrate?

 

[Dan_P]

Is this right...
Organic carbon is used in carbon dosing, denitrifying bacteria eat the Org carbon but this also makes them hungrier for inorganic N, not organic N (per steve above)? The main benefit to this is now these larger bacteria can be removed via filtration taking the N and P with them. So without the filtration later carbon dosing wont work?

Dosing ethanol or acetic acid feeds many, many species of bacteria, and yes, they will take up more nitrogen, getting bigger but then dividing in half to their original size. Overall, there is an increase in the number of bacteria and less nitrogen and phosphorous in the water.

What happens to this larger population of bacteria is a matter of speculation. Some can be removed by the skimmer, some are consumed by other microorganisms, some are consumed by larger organisms, some die, releasing the nitrogen and phosphorous back to the water, and if food is available, the rest keep dividing. When the food runs out, the population will dwindle. No one has figured out what fraction of the bacteria are removed from the system, what portion move up a trophic level by being eaten and what portion have their insides moved into other microorganisms via death.

Corals need N and P, do they eat organic or inorganic N and P? Do they consume the bacteria which contain the N and P? I would think the bacteria would be larger than the individual org or inorg N and P compounds themselves.

Yes, bacteria are very much larger than molecules, more than 1000 times larger. Coral do eat bacteria but they can also assimilate organic and inorganic nitrogen.

Do fuges, socks, skimmer, gac all remove organic N and P but not inorganic, is this because their only large enough to remove when they are inside larger bacteria?

”Fuges” are just small aquariums stocked with macro algae and many species of microorganisms and larger organisms. They work when the stuff in the fuge consumes nitrogen and phosphorous, both organic and inorganic, and the aquarists physically removes the larger population of stuff, usually the macro algae, which results in an overall reduction of nitrogen and phosphorous in the system.

Socks generally remove particles of matter and some of the larger microorganisms. They keep the water clear but probably do not remove that much nitrogen and phosphorous. Inorganics pass through.

GAC removes certain classes of molecules, but again, the actual amount might not be large enough to have a large influence on the amount of nitrogen and phosphorous in the system. I believe inorganic nitrogen and phosphorous pass through.

A skimmer removes a somewhat different class of molecules than GAC. It is not known what fraction of the total nitrogen and phosphorous it removes. The skimmer removes molecules, bacteria, and other small particles. Generally, inorganics pass through unless bound by organic matter.

 

[Nano sapiens]

Socks generally remove particles of matter and some of the larger microorganisms. They keep the water clear but probably do not remove that much nitrogen and phosphorous. Inorganics pass through.

As you mentioned, the removal of particulates and microorganisms also removes phosphorous and nitrogen from the system. By completely removing these items/substances from the system, they no longer have the potential to be converted into inorganics. I sometimes use a filter sock during a weekly cleaning/WC for this purpose and I find it quite effective at keeping NO3 and PO4 in check.

 

[Randy Holmes-Farley Verified Community Expert]

Is this right...
Organic carbon is used in carbon dosing, denitrifying bacteria eat the Org carbon but this also makes them hungrier for inorganic N, not organic N (per steve above)? The main benefit to this is now these larger bacteria can be removed via filtration taking the N and P with them. So without the filtration later carbon dosing wont work?

Corals need N and P, do they eat organic or inorganic N and P? Do they consume the bacteria which contain the N and P? I would think the bacteria would be larger than the individual org or inorg N and P compounds themselves.

Do fuges, socks, skimmer, gac all remove organic N and P but not inorganic, is this because their only large enough to remove when they are inside larger bacteria?

no, bacteria use organic N as well as inorganic N.
The chemicals are all different. Not size only. GAC removes certain types of organics that bind to it, not just large or small. Physical filters like socks cannot remove any individual molecules, only particulates, whether they are organic or inorganic.