How much NO3 and PO4 do you feed in a day? (Plug in your feeding and find out)

[taricha]

Occasionally it's come up that people often test, share, and compare their numbers on nitrate and phosphate tests of their aquarium water, but when talking about feeding, the discussions are much less quantifiable: "Light" "heavy" "a small pinch of this and a fat pinch of that".
For some discussions, quantifying food inputs are probably more useful in understanding how a system is behaving than the leftover NO3 and PO4 a test kit finds in the water.
So for those who want to know but are annoyed by crunching the numbers, here's a calculator aid.

(screenshot)

What you see is the numbers for my system. About 65 gallons, an average daily feeding for my system is around 0.2g of flake, 0.4g of pellets, and a 3g cube of mysis. This works out to about 1.3ppm NO3 and 0.08ppm PO4 inputs as food. This is a pretty light feeding compared to how some other people feed, and my tank gets that on average ~5 days a week. So the weekly average per day is even a bit lower.

Try out the google sheet by clicking the link, and then click (file -> Make a copy) so you edit your own and not the original.



So what's your daily NO3 and PO4 input?

(let me know if it works - I think it should, but I'm not confident.)

 

[Dan_P]

Occasionally it's come up that people often test, share, and compare their numbers on nitrate and phosphate tests of their aquarium water, but when talking about feeding, the discussions are much less quantifiable: "Light" "heavy" "a small pinch of this and a fat pinch of that".
For some discussions, quantifying food inputs are probably more useful in understanding how a system is behaving than the leftover NO3 and PO4 a test kit finds in the water.
So for those who want to know but are annoyed by crunching the numbers, here's a calculator aid.

(screenshot)

What you see is the numbers for my system. About 65 gallons, an average daily feeding for my system is around 0.2g of flake, 0.4g of pellets, and a 3g cube of mysis. This works out to about 1.3ppm NO3 and 0.08ppm PO4 inputs as food. This is a pretty light feeding compared to how some other people feed, and my tank gets that on average ~5 days a week. So the weekly average per day is even a bit lower.

Try out the google sheet by clicking the link, and then click (file -> Make a copy) so you edit your own and not the original.



So what's your daily NO3 and PO4 input?

(let me know if it works - I think it should, but I'm not confident.)

I’ll add when I get back home.

I am looking forwards to the data and your observations

 

[Miami Reef]

Hey. Thanks for this. I stumbled across an issue on my end: I feed LRS Reef Frenzy, but it didn’t supply phosphorus content.

I used the crude protein. Seems like I add about 0.3ppm NO3 per day. That was very enlightening.

Edit: sometimes I’ll add an extra feeding, but mostly it’s around 4g a day.

Thank you so much.

 

[gbroadbridge]

Apparently my average daily input over a week in my ~75gal is

0.867 ppm NO3
0.049 ppm PO4

 

[taricha]

Hey. Thanks for this. I stumbled across an issue on my end: I feed LRS Reef Frenzy, but it didn’t supply phosphorus content.

Using the first listed ingredients: Scallop, Shrimp, Perch, Whitefish....
and Randy's article gives ratios phosphorus/protein:
Scallop: .013, Shrimp: .007, Other white fish: .011
so call it 0.011 approximately.
Label gives 10.4% protein, assume that ratio 0.011, this predicts 10.4% *0.011 = 0.11% phosphorus.

That seems a plausible approximation for the LRS Reef Frenzy, so let's go with it.

 

[taricha]

I used the crude protein. Seems like I add about 0.3ppm NO3 per day. That was very enlightening.

Here's another interesting way to think about it. It means if you did Randy's Ammonia dosing, you could add 0.1ppm ammonia per day and that would literally double your nitrogen input to the system.
Not arguing that you should, just pointing out that we usually think of 0.1ppm total ammonia per day as a very small amount, but in this case, it's more Nitrogen input than your daily feeding routine.

 

[Miami Reef]

Using the first listed ingredients: Scallop, Shrimp, Perch, Whitefish....
and Randy's article gives ratios phosphorus/protein:
Scallop: .013, Shrimp: .007, Other white fish: .011
so call it 0.011 approximately.
Label gives 10.4% protein, assume that ratio 0.011, this predicts 10.4% *0.011 = 0.11% phosphorus.

That seems a plausible approximation for the LRS Reef Frenzy, so let's go with it.

Thank you so much. I don’t know what I’d do without you.

I will have a lot of fun with this calculator. I really appreciate it.

 

[Gumbies R Us]

Well I will be doing this in a little bit, this is an awesome calculator to have on hand!

 

[Dan_P]

Occasionally it's come up that people often test, share, and compare their numbers on nitrate and phosphate tests of their aquarium water, but when talking about feeding, the discussions are much less quantifiable: "Light" "heavy" "a small pinch of this and a fat pinch of that".
For some discussions, quantifying food inputs are probably more useful in understanding how a system is behaving than the leftover NO3 and PO4 a test kit finds in the water.
So for those who want to know but are annoyed by crunching the numbers, here's a calculator aid.

(screenshot)

What you see is the numbers for my system. About 65 gallons, an average daily feeding for my system is around 0.2g of flake, 0.4g of pellets, and a 3g cube of mysis. This works out to about 1.3ppm NO3 and 0.08ppm PO4 inputs as food. This is a pretty light feeding compared to how some other people feed, and my tank gets that on average ~5 days a week. So the weekly average per day is even a bit lower.

Try out the google sheet by clicking the link, and then click (file -> Make a copy) so you edit your own and not the original.



So what's your daily NO3 and PO4 input?

(let me know if it works - I think it should, but I'm not confident.)

Here is the daily feed rate for 6 Green Chromis and a dozen large Mexican Turbos in 100 gallons. I consider myself a generous feeder. There is a 10 gallon Ulva and Caulerpa pond connected to the aquarium to maintain nitrate around 2 ppm and phosphate around 0.4 ppm.

For the snails, I determined their daily food amount by titrating the amount until there were left overs after twenty four hours. For the fish, they are fed until their feeding frenzy slows. I do this 3-5 times a day.

 

[Thales]

Was a bug in the file will repost

 

[Thales]

This is for a big feed

 

[Big E]

Is frozen food being measured after thawing and sifting water out?

 

[taricha]

Is frozen food being measured after thawing and sifting water out?

Nope. Probably better to calculate it for the whole cube mass, as that's what the nutritional value on the label (when present) is written for.
Frozen cubes usually say something like "100g... 32 cubes" or you can just mass the whole frozen hunk of whatever.
When you discard the thaw "water", it's not just water it's also got proteins etc in it from the perforated cells that leak after freezing.

 

[taricha]

This is for a big feed

I love it.
So we have people feeding 0.5-1ppm NO3 eqivalent per day and some people feeding 5+ppm.
This is probably on the very high end of hobby feeding rates per volume, as it should be with mouths like this....

Shot from yesterday. Kinda cleaned the glass. NPS half awake. Guess the phosphate

How close would you say you are to nutrients being stable on those feedings?
I mean, does NO3 and PO4 rise quickly without water changes / lanthanum etc, or does it sit pretty stable (and high)?

 

[KStatefan]

How do you determine the phosphate level for things not listed like Reef Roids or Reef Jerkey

 

[taricha]

How do you determine the phosphate level for things not listed like Reef Roids or Reef Jerkey

Reef Jerky...

if we take this description and makes some guesses about plausible percentages, and use the tables from Randy's article and Google scholar for some papers for organisms not listed in the tables, we can get something like this....

so we might guess reef jerky has a phosphorus/protein ratio around 0.019.
Since they list their % protein as 57%,
then 57%*0.019 = 1.1% phosphorus, which is probably an okay guesstimate.

(None of this is meant to be precise - just to give an idea of the scale of how much N and P we put into our tanks by feeding, measured on a scale that we normally use for those - ppm NO3 and PO4. )

 

[MickeyCT]

Very interesting. I'll figure this out tomorrow. I'm very curious on everyone's results, in particular how much food and size of tank.

 

[Randy Holmes-Farley]

I love it.
So we have people feeding 0.5-1ppm NO3 eqivalent per day and some people feeding 5+ppm.
This is probably on the very high end of hobby feeding rates per volume, as it should be with mouths like this....


How close would you say you are to nutrients being stable on those feedings?
I mean, does NO3 and PO4 rise quickly without water changes / lanthanum etc, or does it sit pretty stable (and high)?

Thanks for this info, taricha.

I'll just add the commentary that the consumption of nitrate may well depend on the nitrate level, and Richard (Thales) has typically had pretty high nitrate (assuming this is the system I am thinking of).

Not because corals or algae necessarily use any more N at 20 ppm nitrate vs 100 ppm nitrate, but because things like denitrification require diffusion of nitrate into pore water, and the rate of diffusion will be directly related to the concentration in the bulk water.

Also, I do not know how important the Anammox process is in reef tanks, but higher ammonia and nitrite from more feeding may also lead to higher removal of N from the system:

NH+4 + NO−2 → N2 + 2 H2O

 

[taricha]

Just for discussion, it gets a little bit wild to me to think about where this stuff goes.
"My fish eat it within a couple of minutes. "
Ok, but that's more of a conversion than a destination. In aquaculture, they uses ballpark numbers like 80% of nitrogen in protein consumed by fish is re-released in ammonia.
Some portion of that ammonia (everything I've seen from measuring surfaces makes me think it's a minority) gets converted to no2/no3.
But whatever portion it is, that's not an end state either- just another conversion.
So where does N actually go?

I'd argue photosynthetic and photosynthetic-associated biomass is the majority. So algae, the inverts that grow by eating it, and coral/symbiont.

If I'm trying to do the accounting to find the N over a week for what went into the tank, those are the organisms that I can see mass accumulations in my tank.
Bacterial biomass could be significant for some people sometimes - but my skimmer never removes much N material. One other thing I can point to in my system is the number of "asterina" stars that multiply over one week. So those represent a significant pathway from nutrients->bacterial/algal biofilms to added mass.

 

[Dan_P]

Just for discussion, it gets a little bit wild to me to think about where this stuff goes.
"My fish eat it within a couple of minutes. "
Ok, but that's more of a conversion than a destination. In aquaculture, they uses ballpark numbers like 80% of nitrogen in protein consumed by fish is re-released in ammonia.
Some portion of that ammonia (everything I've seen from measuring surfaces makes me think it's a minority) gets converted to no2/no3.
But whatever portion it is, that's not an end state either- just another conversion.
So where does N actually go?

I'd argue photosynthetic and photosynthetic-associated biomass is the majority. So algae, the inverts that grow by eating it, and coral/symbiont.

If I'm trying to do the accounting to find the N over a week for what went into the tank, those are the organisms that I can see mass accumulations in my tank.
Bacterial biomass could be significant for some people sometimes - but my skimmer never removes much N material. One other thing I can point to in my system is the number of "asterina" stars that multiply over one week. So those represent a significant pathway from nutrients->bacterial/algal biofilms to added mass.

So, what is your lowest limit of detection for bio-mass? Sometimes, if we can attach some numbers to the discussion, we can make some progress.

Would you estimate 1 lb of bio-mass if a pound of bio-mass was smeared evenly over your aquarium surfaces? On average, amongst friends, how much nitrogen in ppm of nitrate is needed for a pound of bio-mass?