What's in a food - PE Calanus phosphate and potential ammonium (Will shock you)

flampton · Nov 10, 2020

Hi All,

Was just breaking down a specific food I feed to my young fish. They all have tiny mouths currently so PE calanus it is. I was curious how much nitrogen (potential ammonium) and phosphorus (phosphate) was added to my aquarium with each cube. I think the overall numbers will shock you (or maybe not if you knew this info already, haha). Now there is nothing special about this food that makes it bad, this breakdown is going to be close to most proteinaceous seafoods you add to the aquarium, (and maybe a lot better then those rinsed in triphosphate). This is complicated so I put a TLDR at the end.

Okay so the packaging gives you some clues

Focus down in the bottom left corner and find Phosphorus (MIN) 0.2%. This means that there is at minimum 0.2% phosphorus in each cube. Now a cube weighs 0.1 OZ (40 cubes /4oz package). We will convert that to grams which is 2.835 grams or 2835 mg. This means if I multiply the weight of the cube by the phosphorus percentage I can get the P per cube.

2835 x 0.002 = 5.67 mg of P per cube

Now this is just phosphorus, and living things only have phosphate so we can see how much is in there by taking the MW of Phosphate and dividing by the MW of phosphorus and multiplying it by the amount of mg

94.97/30.97 x 5.67 mg P = 17.4 mg of phosphate per cube

Lets do nitrogen next. From various scientific studies the Nitrogen

hosphorus ratio of Calanus copepods is about 20:1. So I can use this number to figure out how much nitrogen is in the product. (This will get tricky so bear with me as I need to move to moles)

17.4/94.97 = 0.18 mmoles of phosphate. So that means that we can multiple this number by 20 and get 3.6 mmoles of nitrogen in the product. Now I can convert back to mg by multiplying by nitrogen's MW of 14.

3.6 mmoles x 14 = 50.4 mg of nitrogen

Now this is just nitrogen and so if we want ammonium potential we need to multiply those N mmoles by the molecular weight of ammonium which is 18.

3.6 mmoles x 18 = 64.8 mg of potential ammonium

So conclusion and TLDR
WOW okay now what does this mean? Well lets say you have a 20 gallon aquarium (76 liters) and use 1 cube of calanus once or twice a day. Here is the resulting potentials if the food only has that minimum amount of phosphorus

1 cube added
0.23 ppm PO4 added to the aquarium
1.17 ppm NH4 potential added

2 cubes added
0.46 ppm PO4 added
2.34 ppm NH4 potential added

Now you hope all that goes into building mass of your livestock, but it just doesn't work that way because many many factors. The main one being that carbon is required for energy by the heterotrophs in your aquarium. Well I'm definitely not going to get into respiration rates etc... so I guess just trust me that there isn't enough carbon in this food (or any food for that matter) that won't cause your fish and other multicellular animals to excrete some amount of ammonium and phosphate. Oh and they're still going to waste a bunch of those organic carbons in other ways besides breathing e.g. feces, mucus layers, shedding etc. So I have no idea what the feed conversion is but I'd be extremely happy with 10% for growing fish thus utilizing 10% of the nitrogen and 10% of the phosphate. An adult fish who is done growing will conserve 0% of the nitrogen and phosphate.

Think of an adult person eating 2000 calories from beef jerky (no water weight). 2000 calories is their maintenance so that means this person is consuming 483 grams of beef jerky a day (1.06 pounds) but not gaining any weight. That means they must be losing that much carbo, nitrogen and phosphate everyday to maintain.

Oh and the reason for ammonium is because that is the main version in the tank. At pH 8.2 the water will have 93% ammonium and 7% ammonia. And their molecular weights are only 1 apart. Basically would have negligible effect on the results to use the combined MW of 17.93.

Hope you made it this far! haha

jda · Nov 10, 2020

I read the whole thing. I have often wondered about this stuff since, in the past, the assay is from dry and the food has much water in it. No idea how this one is calculated.

Dr. RHF has posted before that the "stuff" gets used and kept 1/3 with each cycle that gets to it (paraphrasing)... 1/3 to the fish that eat it, 1/3 to fish the next time (fish are the #1 consumer of other fish poop), 1/3 to the first bacteria or microfauna to get to it, or whatever... then pretty much nothing left after that. This is all in theory, though, since po4 does accumulate, so we know that not all of it is taken up and kept by growing things.

I welcome the ammoni[a,um]... great for the corals and clams.

I am a big fan of heavy import and heavy export. With all of what is available if you feed well, you can see why the tank thrives when you do. The key is exporting it just as well so that residual levels stay low.

flampton · Nov 10, 2020

jda said:
I read the whole thing. I have often wondered about this stuff since, in the past, the assay is from dry and the food has much water in it. No idea how this one is calculated.

Dr. RHF has posted before that the "stuff" gets used and kept 1/3 with each cycle that gets to it (paraphrasing)... 1/3 to the fish that eat it, 1/3 to fish the next time (fish are the #1 consumer of other fish poop), 1/3 to the first bacteria or microfauna to get to it, or whatever... then pretty much nothing left after that. This is all in theory, though, since po4 does accumulate, so we know that not all of it is taken up and kept by growing things.

I welcome the ammoni[a,um]... great for the corals and clams.

I am a big fan of heavy import and heavy export. With all of what is available if you feed well, you can see why the tank thrives when you do. The key is exporting it just as well so that residual levels stay low.

I did the above exercise because of my export style which is carbon dosing (bacteriologist so love them bacteria) so by doing the above I can estimate the needed carbon to grow enough bacteria to remove the excess nitrogen (and phosphate, but need extra nitrogen to support this process)

As I am too in favor of heavy import export methods. I think I posted this for a few reasons.
1. People wondering how their nitrates get to 100
2. People wondering how their phosphates get to 5
3. Why controlled feeding is not the best option (I'll explain in a second)
4. For people who think dosing ammonium is crazy. (I'm currently dosing ~ 70mg daily in my 70 gallons total (about 0.25 ppm). Yet this is probably just a tenth of what the tank receives in foods.

As far as one clearly people will understand feeding too much without proper export they'll get high nitrates.

However, phosphates are a bit different because food ratios are usually higher in phosphates than needed. PLUS phosphates have no gaseous phase.

Finally as far as controlling nutrients by feeding less. This will work to a point, then what you'll find is starvation in various organisms and possibly a crash. E.g. if your fish need four cubes to stay healthy and thrive but your phosphates and nitrates are high, well going to three cubes is counterproductive. You need to fix your export systems to handle four cubes a day. This obviously gets way more complicated when feeding coral, but you get the idea.

jda · Nov 10, 2020

Feeding less means less availability and, as we know, residual levels are fools gold and availability is the prize - hard to convince others of this. I never recommend feeding less... the causes more unintended damage than people know.

One reason that P is builds up so quickly is that it is mostly excreted in urine and not so much in feces where it can be uptook by other solid-food-eaters to be used. It seems that once converted from food to urine, this part of the cycle stops for a lot of it - I am not smart enough to calculate how much ends up in the feces and eaten downstream (from the article below, if the link still works. Another quote from Dr. RHF (context: this was from a thread where people thought that the sandbed was full of phosphate and was leeching - we also know that anything that hits the sand with anything usable will be consumed):

I am, as it happens, an expert on phosphate metabolism. I've studied it for more than 20 years, and have invented products that sell more than a billion dollars worth each year correcting hyperphosphatemia in people.

There is a flow chart in this link which shows the relative excretion of phosphate in urine (which is almost totally inorganic phosphate) and in feces (which is a combination of organic and inorganic phosphate).

https://www.inkling.com/read/medica...-2nd/chapter-52/calcium-and-phosphate-balance

The inorganic phosphate in urine excretion dominates, even if you ignore all of the inorganic phosphate in the feces. Then you seem to assume that all of that feces ends up in the substrate, which is utterly untrue. Other macroscopic creatures eat it, sometimes over and over. I had a kole tang that loved to eat my yellow tangs feces as fast is it came out. That drops the original phosphate ending up in feces by another factor of three. Each cycle drops it significantly.

I am not a fan of organic carbon dosing since I don't want waterborne bacteria to consume all of the available "good stuff" and outcompete my corals. However, I have no actual evidence that this happens, just anecdotes and some experiences that my corals in a few tanks at a few different times did not care for organic carbon dosing (not just a single incident). It is good at residual level reduction.

Subsea · Dec 22, 2020

jda said:
Feeding less means less availability and, as we know, residual levels are fools gold and availability is the prize - hard to convince others of this. I never recommend feeding less... the causes more unintended damage than people know.

One reason that P is builds up so quickly is that it is mostly excreted in urine and not so much in feces where it can be uptook by other solid-food-eaters to be used. It seems that once converted from food to urine, this part of the cycle stops for a lot of it - I am not smart enough to calculate how much ends up in the feces and eaten downstream (from the article below, if the link still works. Another quote from Dr. RHF (context: this was from a thread where people thought that the sandbed was full of phosphate and was leeching - we also know that anything that hits the sand with anything usable will be consumed):

Finally, mechanical filtration in the form of skimming but not GAC does provide an effective means of bacteria export, at least up to a point. It appears likely that some types of bacteria are indeed “skimmable”, but others are not. Thus, skimming inadvertently provides severe (?) evolutionary pressure to skew the tank’s resident water column bacteria population to favor the “non-skimmable” cohort.]

I am not a fan of organic carbon dosing since I don't want waterborne bacteria to consume all of the available "good stuff" and outcompete my corals. However, I have no actual evidence that this happens, just anecdotes and some experiences that my corals in a few tanks at a few different times did not care for organic carbon dosing (not just a single incident). It is good at residual level reduction.

Ken Feldman & Sanjay Joshi research paper has detailed a study of bacteria in a reef tank. I have read Feldman’s initial research, but this is a differrent paper with Sanjay Joshi. It might open some eyes on nutrient management in a reef tank.

Bacterial Counts in Reef Aquarium Water: Baseline Values and Modulation by Carbon Dosing, Protein Skimming, and Granular Activated Carbon Filtration

What are the bacteria populations in the water column of reef tanks, and how does that value compare with bacterial counts in authentic reef water? Does carbon dosing indeed increase water column bacteria populations (i.e., is growth carbon limited)? Does mechanical filtration (protein skimming...

reefs.com

[Finally, mechanical filtration in the form of skimming but not GAC does provide an effective means of bacteria export, at least up to a point. It appears likely that some types of bacteria are indeed “skimmable”, but others are not. Thus, skimming inadvertently provides severe (?) evolutionary pressure to skew the tank’s resident water column bacteria population to favor the “non-skimmable” cohort.]

jda · Dec 22, 2020

My new online friend flampton is on this board (and this thread) and is a bacterialologist, or something close to that. He has a lot of great posts on bacteria and is smart if you ever have a question. He is running a tank with alternative methods to keep tank bacteria populations higher than normal tanks.

A few PMs with him has lead me to read arch more into bacteria, but each answer has spawned even more questions.

I think that it important to note that it appears that all dead bacteria are skimmable, which needs consideration if you are wondering about the ability to remove bacteria with a skimmer. The addition of live ones might be a rounding error in comparison, but nobody really knows.

Randy Holmes-Farley · Dec 22, 2020

This is the article referred above where I discuss phosphate levels in foods.

Aquarium Chemistry: Phosphate And Math: Yes You Need To Understand Both

Foods are by far the most important source of phosphate in most aquariums. In considering whether sources of phosphate other than foods are important, one must carefully look to the actual amounts involved to determine whether other sources are even worth trying to minimize.

reefs.com

from it:

Conclusion
Foods are by far the most important source of phosphate in most aquariums. While there are big variations between foods, it does not appear in this analysis that dry foods are the nasties they are often made out to be, relative to frozen foods. There are better and poorer choices (with respect to phosphate) to be made within each food type. Avoiding foods with bones, however, might be worthwhile if delivering less phosphate is a goal. Additionally, fresh grocery store shrimp seems to be one of the best foods from this standpoint.

In considering whether sources of phosphate other than foods are important, one must carefully look to the actual amounts involved to determine whether other sources are even worth trying to minimize. It can be scary to learn that your purified fresh water has phosphate in it, or that your salt mix has detectable phosphate, or that your supplements or whatever have some phosphate. But just because you detect something, and maybe you even detect a concentration far higher than in your aquarium, that does not by any means imply that those sources are significant enough to warrant some sort of corrective action. Our analytical tools have become fairly sensitive, allowing us to detect things which might sound like trouble, but really aren’t. We need to understand the various dilution issues involved as well as the overall phosphate balance in a reef aquarium to evaluate the importance of different measurements.

Just use some math and put it all into perspective, before using some dollars or time to chase a trivial “problem”.

flampton · Dec 22, 2020

Subsea said:
Ken Feldman & Sanjay Joshi research paper has detailed a study of bacteria in a reef tank. I have read Feldman’s initial research, but this is a differrent paper with Sanjay Joshi. It might open some eyes on nutrient management in a reef tank.

Bacterial Counts in Reef Aquarium Water: Baseline Values and Modulation by Carbon Dosing, Protein Skimming, and Granular Activated Carbon Filtration

What are the bacteria populations in the water column of reef tanks, and how does that value compare with bacterial counts in authentic reef water? Does carbon dosing indeed increase water column bacteria populations (i.e., is growth carbon limited)? Does mechanical filtration (protein skimming...

reefs.com

[Finally, mechanical filtration in the form of skimming but not GAC does provide an effective means of bacteria export, at least up to a point. It appears likely that some types of bacteria are indeed “skimmable”, but others are not. Thus, skimming inadvertently provides severe (?) evolutionary pressure to skew the tank’s resident water column bacteria population to favor the “non-skimmable” cohort.]