Biopellets reduce N and P in a 16:1 ratio, can I dose N (not NO3) to reduce PO4 further and achieve a 10:1 ratio?

Muffin87

Community Member
Review score
+0 /0 /-0
View Badges
Joined
Aug 12, 2019
Messages
90
Reaction score
31
Review score
+0 /0 /-0
This quote summarises my current understanding of nutrient reduction with biopellets:
Biopellets tend toward the reduction of nitrates by boosting the organisms that feed on them. Phosphates will naturally reduce by a certain amount in relationship to the reduction of nitrates. That is somewhere around a 16:1 ratio, whereby a reduction of 16 parts of nitrate will see a reduction of 1 part of phosphate.
With biopellet systems, we’re reducing nitrates at a level faster than we can reduce phosphates. Nitrates will often become undetectable when using solid carbon dosing such as what we are accomplishing with biopellets. The remaining phosphates, then, become food for cyanobacteria if it is not skimmed from the water column. It is imperative that the hobbyist remove phosphates from the system at a level that matches that of the nitrate reduction. (https://blog.marinedepot.com/2014/05/biopellets-beginners-guide.html)
If biopellets reduce N and P in a 16:1 ratio, then it follows that by providing excessive nitrogen (not NO3), phosphate should be reduced further, while nitrate should still be at an undetectable level.
Can I dose N (not NO3) to make biopellets reduce PO4 further, and achieve a 10:1 ratio?
For example, I could dose ATI nutrition N, or Tropic Marin Amino-Organic (the latter contains organic nitrogen compounds).

I realise that if that were possible then more people would be doing that, and certainly I might be missing something really obvious, but I'm just not sure why I can't/shouldn't tweak the ratio of nutrients to alter their eventual ratio after reduction by bacteria.

What am I missing?

Thanks a lot!
 
AquaCave Logo Banner

Dan_P

2500 Club Member
Review score
+0 /0 /-0
View Badges
Joined
Sep 21, 2018
Messages
2,700
Reaction score
2,743
Review score
+0 /0 /-0
This quote summarises my current understanding of nutrient reduction with biopellets:

If biopellets reduce N and P in a 16:1 ratio, then it follows that by providing excessive nitrogen (not NO3), phosphate should be reduced further, while nitrate should still be at an undetectable level.
Can I dose N (not NO3) to make biopellets reduce PO4 further, and achieve a 10:1 ratio?
For example, I could dose ATI nutrition N, or Tropic Marin Amino-Organic (the latter contains organic nitrogen compounds).

I realise that if that were possible then more people would be doing that, and certainly I might be missing something really obvious, but I'm just not sure why I can't/shouldn't tweak the ratio of nutrients to alter their eventual ratio after reduction by bacteria.

What am I missing?

Thanks a lot!
I follow your logic. Couple ideas.

When dosing organo-nitrogen compounds to a system, for example amino acids, microorganisms like cyanobacteria that you do not want around might be encouraged to grow.

Adding organo-nitrogen compounds could have the same effect as dosing ammonia. Could you just dose ammonium chloride instead?

Make life easy, dose nitrate.
 

Randy Holmes-Farley

Reef Chemist
Review score
+0 /0 /-0
View Badges
Joined
Sep 5, 2014
Messages
46,577
Reaction score
35,993
Review score
+0 /0 /-0
Location
Arlington, Massachusetts, United States
This quote summarises my current understanding of nutrient reduction with biopellets:

If biopellets reduce N and P in a 16:1 ratio, then it follows that by providing excessive nitrogen (not NO3), phosphate should be reduced further, while nitrate should still be at an undetectable level.
Can I dose N (not NO3) to make biopellets reduce PO4 further, and achieve a 10:1 ratio?
For example, I could dose ATI nutrition N, or Tropic Marin Amino-Organic (the latter contains organic nitrogen compounds).

I realise that if that were possible then more people would be doing that, and certainly I might be missing something really obvious, but I'm just not sure why I can't/shouldn't tweak the ratio of nutrients to alter their eventual ratio after reduction by bacteria.

What am I missing?

Thanks a lot!

The ratio is very unlikely to be exactly what you suggest, but the general issue with any balanced method that reduces N and P is that you may need to export one more than the other and the method will not get you there.

Many folks dose N or P (or both) to alleviate this problem. Some folks (such as myself) also use methods that are more focused on the one you want to remove (organic carbon for N, GFO for phosphate, for example).
 
OP
M

Muffin87

Community Member
Review score
+0 /0 /-0
View Badges
Joined
Aug 12, 2019
Messages
90
Reaction score
31
Review score
+0 /0 /-0
Many folks dose N or P (or both) to alleviate this problem
I just don't understand if adding N is purely gonna adjust the nutrients to a more desirable ratio without lowering P, or if adding N can drive bacteria to lower P further.
Could you clarify that for me?

Thanks a lot for your expertise!
 
Top Shelf Aquatics

Randy Holmes-Farley

Reef Chemist
Review score
+0 /0 /-0
View Badges
Joined
Sep 5, 2014
Messages
46,577
Reaction score
35,993
Review score
+0 /0 /-0
Location
Arlington, Massachusetts, United States
I just don't understand if adding N is purely gonna adjust the nutrients to a more desirable ratio without lowering P, or if adding N can drive bacteria to lower P further.
Could you clarify that for me?

Thanks a lot for your expertise!

Forget ratios. IMO, they are not a useful way to think about nutrients.

Target N and P to appropriate levels, regardless of the other one.

it is misguided, for example, to make one excessively low or high just because the other one is.

Adding N or P will only help lower the other one if it is a limiting factor in growth of something (such as macroalgae).
 

Toys For Kids Drive

Untitled-2 copy.jpg

What's the first coral you ever bought?

  • An invasive soft coral

    Votes: 69 18.2%
  • Zoanthids

    Votes: 99 26.1%
  • Mushrooms

    Votes: 58 15.3%
  • Other Soft Coral

    Votes: 49 12.9%
  • LPS

    Votes: 85 22.4%
  • SPS

    Votes: 10 2.6%
  • Other (please explain)

    Votes: 9 2.4%
Top