nitrate / phosphate absorption rate

[jarviz]

Does macroalgae ( or red gracilaria in my case) soak up nitrates and phosphates drastically different? i have close to 0 nitrates and about 0.12 phosphates. i do have phosguard in and my rocks may be leeching phosphates, but i'm just trying to understand the macros uptake capabilities a little better just so i know how to get my nitrates up without throwing my phosphate numbers off.

 

[Spare time]

I believe that they should use more nitrate than phosphate as living things tend to use way more nitrate than phosphate for a variety of purposes.

Macroalgae that runs out of nitrate probably won't be able to lower the phosphates in a tank as they need both to grow.

Once you get the phosphate lower, the macro algae should be able to handle both of them given ideal lighting and what not.

 

[jarviz]

I believe that they should use more nitrate than phosphate as living things tend to use way more nitrate than phosphate for a variety of purposes.

Macroalgae that runs out of nitrate probably won't be able to lower the phosphates in a tank as they need both to grow.

Once you get the phosphate lower, the macro algae should be able to handle both of them given ideal lighting and what not.

interesting... but food and fish waste gives off way more phosphates than nitrates right?

 

[Spare time]

interesting... but food and fish waste gives off way more phosphates than nitrates right?

From what I understand, there is a lot more phosphorus in fish foods than needed so they do release that in their feces, but as to how much a fish gives off of both likely varies dramatically between species, age, environmental factors, etc. The amount of ammonia a fish puts out is primarily dependent on protein intake and metabolic efficiency of the fish. Phosphate output is often dependent on the phosphate content of where the fish is getting protein from (and also depends on the fish species).

https://www.pesca.sp.gov.br/34_4_591-600.pdf

 

[Spare time]

Randy has a write up on phosphate with a section on macroalgae.
http://reefkeeping.com/issues/2006-09/rhf/index.php#12

 

[Subsea]

Gracilaria Parvispora, Red Ogo, has a N ration of 16:1

 

[jarviz]

Gracilaria Parvispora, Red Ogo, has a N ration of 16:1

Does that mean it absorbs 16ppm of nitrate while absorbing 1ppm of phosphates? so i would really need to raise my nitrates without touching my phosphates lol

 

[Subsea]

Does that mean it absorbs 16ppm of nitrate while absorbing 1ppm of phosphates? so i would really need to raise my nitrates without touching my phosphates lol

The goal is not to necessarily have 16 fold of N concentration in water, the goal is to have detectable levels of nitrate so macro can grow.

 

[jarviz]

The goal is not to necessarily have 16 fold of N concentration in water, the goal is to have detectable levels of nitrate so macro can grow.

I'm not trying to have 16x nitrate. I was trying to understand how macro affects my nitrates vs phosphate numbers. Since I also have phosguard but getting near 0 nitrates and about .1 phosphates. Just wanted to figure out how to raise nitrates with out raising phosphates.

 

[Subsea]

I'm not trying to have 16x nitrate. I was trying to understand how macro affects my nitrates vs phosphate numbers. Since I also have phosguard but getting near 0 nitrates and about .1 phosphates. Just wanted to figure out how to raise nitrates with out raising phosphates.

Add potassium nitrate, stump remover from Home Depot. I use ammonia.

 

[Subsea]

@jarviz

My bad: The Redfield Ratio of phytoplankton is 16:1
nitrogen to phosphate. Macroalgae ratio of N depending on species the N ratio is as high as 80:1.

when I grew Red Ogo for commercial sale to Oriental restaurants, dry bio analysis showed 30:1 for N

 

[Garf]

Fish give off ammonia constantly which algae can use, so although nitrate may be undetectable, algae and other stuff can survive and grow. This makes nitrate testing a bit redundant with regard to algae growth. Same as phosphate. Detectable phos and nitrate are just a “buffer / excess”. Running at really low/ undetectable levels means you need a regular supply. At least in my mind.

 

[ClownWrangler]

@jarviz

My bad: The Redfield Ratio of phytoplankton is 16:1
nitrogen to phosphate. Macroalgae ratio of N depending on species the N ratio is as high as 80:1.

when I grew Red Ogo for commercial sale to Oriental restaurants, dry bio analysis showed 30:1 for N

I came across your post from 2014 at reef central. I was confused about nitrate to phosphate ratio vs nitrogen to phosphorus ratio and which is implied in which cases. Standard NPK ratios go by nitrogen/phosphorus. Here's what I'm referring to.

Agriculture lab results for Gracilaria Parvispora are:

Nitrogen. 2.6 %
Phosphorous 0.08%
Potassium. 13.5%
Calcium. 0.55%
Magnesium. 1.16%
Sulfur. 4.80%
Zinc. 139 ppm
Iron. 107 ppm
Manganese. 20 ppm
Cooper. 7 ppm

This would be a ratio of 32.5:1 for N/P

But it would be a ratio of 47:1 for nitrate/phosphate
I was thinking of shooting for an Even 50:1 for nitrate/phosphate in a mixed macro only tank, does this sound reasonable? Or would it benefit from more phosphate? Something closer to the redfield ratio?

 

[ClownWrangler]

@jarviz

My bad: The Redfield Ratio of phytoplankton is 16:1
nitrogen to phosphate. Macroalgae ratio of N depending on species the N ratio is as high as 80:1.

when I grew Red Ogo for commercial sale to Oriental restaurants, dry bio analysis showed 30:1 for N

There is a lot of talk about N/P ratio, but what about K. It looks like the K demand is higher than both N and P, but nobody talks about that. The analysis I posted above shows a N/K ratio of 1:5.2. Potassium nitrate has a ratio of 1:2.8. Is this close enough?

 

[Subsea]

I came across your post from 2014 at reef central. I was confused about nitrate to phosphate ratio vs nitrogen to phosphorus ratio and which is implied in which cases. Standard NPK ratios go by nitrogen/phosphorus. Here's what I'm referring to.

Agriculture lab results for Gracilaria Parvispora are:

Nitrogen. 2.6 %
Phosphorous 0.08%
Potassium. 13.5%
Calcium. 0.55%
Magnesium. 1.16%
Sulfur. 4.80%
Zinc. 139 ppm
Iron. 107 ppm
Manganese. 20 ppm
Cooper. 7 ppm

This would be a ratio of 32.5:1 for N/P

But it would be a ratio of 47:1 for nitrate/phosphate
I was thinking of shooting for an Even 50:1 for nitrate/phosphate in a mixed macro only tank, does this sound reasonable? Or would it benefit from more phosphate? Something closer to the redfield ratio?

It is not necessary to change ratio of nutrients in bulk water, only that there is sufficient nutrients. The higher the concentration does not determine growth rate but a major or trace nutrient deficiency will limit growth