Randy's Elements to Dose

[Randy Holmes-Farley]

Thank you for putting this together!


A couple of issues:
Phosphorus is listed but the dosing notes have the value in ppm (the concentration unit we commonly use for phosphate).

Also, small typo below.

Thanks. Fixed the P to read as 0.02 ppm phosphate

 

[Doctorgori]

We can dig into anything folks want.

I listed iodine as may be worth supplementing. Its hard for that statement to be wrong, but I’m certainly aware that some folks claim to find a big benefit and some do not dose it and are happy with their aquaria.

There’s also no drawback to dosing iodide to natural levels.

Randy this is curiosity. not confrontation but I thought you. were kinda skeptical on iodine dosing ( paraphrasing/abridging, can’t locate the exact quote)

My personal experience. is weakly anecdotal in that I could swear I see a noticeable “perkiness” in softies dosing iodine… the results were somewhat repeatable but admittedly no scientific journaling or methodology was applied… just wish a more educated and competent eyeballs have observed this

As far as I can tell from folks posting here. Moonshiners recommends some elements that I do not believe have evidence to make them worth dosing. Barium, lithium, and rubidium, for example.

That said, there's also nothing wrong with dosing them to natural levels.

Again, as far as I can tell from folks posting here (I do not go to facebook pages and such), most moonshiners seem to follow most or all of the plan, hence someone saying their results are great has little to no bearing on whether any particular part of it is just wasted effort.

It requires some sort of comparative testing of elements one at a time to say anything convincing, especially if the world of science does not recognize a biological role for these elements in ANY organism.

I’ve always wondered if it’s a case of “you don’t know what you need until you miss it” thing …
I’m no chemist/biologist but can organic tissue, proteins, or whatever been manufactured strictly from the grocery list of essential trace elements provided and one simply add sunlight and water?
…I dunno

 

[Randy Holmes-Farley]

Randy this is curiosity. not confrontation but I thought you. were kinda skeptical on iodine dosing ( paraphrasing/abridging, can’t locate the exact quote)

My personal experience. is weakly anecdotal in that I could swear I see a noticeable “perkiness” in softies dosing iodine… the results were somewhat repeatable but admittedly no scientific journaling or methodology was applied… just wish a more educated and competent eyeballs have observed this

I’ve always wondered if it’s a case of “you don’t know what you need until you miss it” thing …
I’m no chemist/biologist but can organic tissue, proteins, or whatever been manufactured strictly from the grocery list of essential trace elements provided and one simply add sunlight and water?
…I dunno

I'm skeptical of some claims (shrimp) more than others (zooanthids look better), but I have it listed as worth considering as there are numerous organisms that take it up:

Another set of creatures of the deep that use iodine are certain gorgonia, such as Plexaura flexuosa. They have 3,5-diiodotyrosine in their bodies, to the tune of 0.1 to 2.6% of the total dry weight as iodine. This iodoamino acid is presumably incorporated into proteins in the skeleton (stem), but the benefit is unclear.

IMO, there's no reason to not at least experiment with it. It did not appear useful in my testing.

 

[Bruce Burnett]

So many things to possibly dose. So many variables, age of tank, how often and how large the water changes are, they types of food. How calcium and magnesium are maintained. I can see how it is not possible to just give a dosing amount for every tank.

 

[gws3]

@Randy Holmes-Farley Is your cobalt concentration of 6 ng/L intentional? I typically see NSW concentrations on the magnitude of 0.Xμg/L or 0.0Xμg/l referenced, 0.006μg/L seems very low.

 

[gbroadbridge]

In a previous article I discussed my thoughts on trace elements

Randy's thoughts on trace elements

Randy's thoughts on trace elements in reef aquaria.

www.reef2reef.com

This article expands on that discussion by providing specific guidance for all elements one might dose.

First, some explanation.

I have listed many elements as not recommended to dose based on the lack of evidence of a requirement in ANY known organism. These are shown in a lavender color on the table below. I see no rationale to dose these, despite many being at odds with recommendations that permeate the reefing community. In many cases those recommendations may stem from the false assumption that if a coral skeleton deposits an element, it must be useful for the coral. That assumption is just not true. Precipitating calcium carbonate incorporates all sorts of elements from seawater that have no benefit, up to and including uranium. Barium seems to fit that idea, and I reject the idea that it is needed or useful. Also colored in lavender are a few elements that are only known to be used by a single microorganism that is unlikely to be important in any reef tank, and they drop off the dosing list. Cadmium is such an example.

Second, just because I recommend an element DOES NOT mean I agree with the wide ranging claims for those elements. I do not believe strontium is useful for hard corals, for example, but it does have uses in other organisms and makes the dosing list. Likewise, I do not believe shrimp need iodine, but it makes the dosing list because it is used by other organisms such as some gorgonia.

Third, some elements may be required by some or even many organisms but also may have the potential for toxicity if overdosed and one needs to be very careful dosing these. These elements include copper and arsenic.

Finally, some elements lack much info on what happens if they are not maintained at all, and these I have put in the experiment category, even if there are organisms somewhere known to use then. Fluoride, arsenic, tin, and tungsten fit this category.

Recommendations

Before getting to anything else, note that a yes for dosing in the table below does not mean it needs to be dosed in all tanks. It means that it may be needed if levels are sufficiently low. I do not recommend individual random dosing without measurement except for iron, manganese and silicate that are all rapidly depleted and show little harm from overdosing. That said, dosing certain commercial trace element mixes without measurement may be acceptable depending on the system and the reliability of the company providing the solution and dosing guidelines.

The table below recommends dosing a variety of major ions as needed (e.g., potassium, calcium, magnesium, etc.), but those are not the point of this article. Two elements (N as nitrate and P as phosphate) also make the list to maintain, and sometimes are considered trace elements, but are not the main focus of this article.

Two trace elements warrant special attention since they rapidly deplete and are used by a great many organisms: iron and manganese. If you dose no other trace elements, these two would be the two I'd pick.

I recommend silicate dosing if you care about either sponges, or the ability of diatoms to displace more problematic pests from surfaces such as rocks.

There are a number of other trace elements that are very important for organisms (e.g., vanadium). Whether these get low enough to warrant dosing may be system dependent, and reefers lack good info on what levels are too low for any given organism we keep, but it is not hard to maintain detectable levels and/or look for biological effects when dosing.

I'm sure many folks will be disappointed that I am not providing a specific concentration target or range for each element. The reason I do not, even when others do so, is because I do not think there is sufficient data to make such recommendations. Even recommending natural levels is fraught with problems. This is why:

1. Accurate measurement of trace elements is not assured even by using and type of ICP. Proper procedures need to be followed, and we rarely have such info.

2. The chemical form present in an aquarium greatly impacts it bioavailability and toxicity. These chemical forms can include oxidations tates 9e.g., iodide and iodate for iodine) and in the binding of the elements by organic matter (e.g., copper is known to be nearly completely bound by organics in the ocean, significantly reducing its toxicity realtive to bare copper ion.

3. Reef hobbyists keep a very wide range of organisms. if someone suggests a particular target concentration for a trace element, what organism is that based on? Do you even keep that organism?

4. Even knowing the chemical form of trace element in a reef tank (we do not) and somehow matching it to the ocean concentration (where and at what depth), the ocean itself may not be optimal. Iron is known to be limiting to the growth of some organisms in the ocean. Do we want to have that same limitation, or not?

To this end, I provide the whole ocean average concentration in the table below. Trace elements vary by depth and by location. Iron and silicate, for example, are greatly depleted in surface water relative to deeper water because of organisms grabbing them up as fast as they can. That said, ocean concentrations can be at least a very rough guide to whether trace elements measured by ICP may be too low or too high.

All of these thoughts are just my opinion, and I recognize that others have divergent opinions on what should be done about trace elements. I welcome any discussions, corrections, clarifications, or differences of opinion in the thread that is associated with this article.

Since the table may not read well on all devices, i have attached the table as a pdf as well.

Happy Reefing!

Thanks for spending the time and effort putting this paper together.

I guess I'll save the Erbium for the dowels

 

[GuppyHJD]

In a previous article I discussed my thoughts on trace elements

Randy's thoughts on trace elements

Randy's thoughts on trace elements in reef aquaria.

www.reef2reef.com

This article expands on that discussion by providing specific guidance for all elements one might dose.

First, some explanation.

I have listed many elements as not recommended to dose based on the lack of evidence of a requirement in ANY known organism. These are shown in a lavender color on the table below. I see no rationale to dose these, despite many being at odds with recommendations that permeate the reefing community. In many cases those recommendations may stem from the false assumption that if a coral skeleton deposits an element, it must be useful for the coral. That assumption is just not true. Precipitating calcium carbonate incorporates all sorts of elements from seawater that have no benefit, up to and including uranium. Barium seems to fit that idea, and I reject the idea that it is needed or useful. Also colored in lavender are a few elements that are only known to be used by a single microorganism that is unlikely to be important in any reef tank, and they drop off the dosing list. Cadmium is such an example.

Second, just because I recommend an element DOES NOT mean I agree with the wide ranging claims for those elements. I do not believe strontium is useful for hard corals, for example, but it does have uses in other organisms and makes the dosing list. Likewise, I do not believe shrimp need iodine, but it makes the dosing list because it is used by other organisms such as some gorgonia.

Third, some elements may be required by some or even many organisms but also may have the potential for toxicity if overdosed and one needs to be very careful dosing these. These elements include copper and arsenic.

Finally, some elements lack much info on what happens if they are not maintained at all, and these I have put in the experiment category, even if there are organisms somewhere known to use then. Fluoride, arsenic, tin, and tungsten fit this category.

Recommendations

Before getting to anything else, note that a yes for dosing in the table below does not mean it needs to be dosed in all tanks. It means that it may be needed if levels are sufficiently low. I do not recommend individual random dosing without measurement except for iron, manganese and silicate that are all rapidly depleted and show little harm from overdosing. That said, dosing certain commercial trace element mixes without measurement may be acceptable depending on the system and the reliability of the company providing the solution and dosing guidelines.

The table below recommends dosing a variety of major ions as needed (e.g., potassium, calcium, magnesium, etc.), but those are not the point of this article. Two elements (N as nitrate and P as phosphate) also make the list to maintain, and sometimes are considered trace elements, but are not the main focus of this article.

Two trace elements warrant special attention since they rapidly deplete and are used by a great many organisms: iron and manganese. If you dose no other trace elements, these two would be the two I'd pick.

I recommend silicate dosing if you care about either sponges, or the ability of diatoms to displace more problematic pests from surfaces such as rocks.

There are a number of other trace elements that are very important for organisms (e.g., vanadium). Whether these get low enough to warrant dosing may be system dependent, and reefers lack good info on what levels are too low for any given organism we keep, but it is not hard to maintain detectable levels and/or look for biological effects when dosing.

I'm sure many folks will be disappointed that I am not providing a specific concentration target or range for each element. The reason I do not, even when others do so, is because I do not think there is sufficient data to make such recommendations. Even recommending natural levels is fraught with problems. This is why:

1. Accurate measurement of trace elements is not assured even by using and type of ICP. Proper procedures need to be followed, and we rarely have such info.

2. The chemical form present in an aquarium greatly impacts it bioavailability and toxicity. These chemical forms can include oxidations tates 9e.g., iodide and iodate for iodine) and in the binding of the elements by organic matter (e.g., copper is known to be nearly completely bound by organics in the ocean, significantly reducing its toxicity realtive to bare copper ion.

3. Reef hobbyists keep a very wide range of organisms. if someone suggests a particular target concentration for a trace element, what organism is that based on? Do you even keep that organism?

4. Even knowing the chemical form of trace element in a reef tank (we do not) and somehow matching it to the ocean concentration (where and at what depth), the ocean itself may not be optimal. Iron is known to be limiting to the growth of some organisms in the ocean. Do we want to have that same limitation, or not?

To this end, I provide the whole ocean average concentration in the table below. Trace elements vary by depth and by location. Iron and silicate, for example, are greatly depleted in surface water relative to deeper water because of organisms grabbing them up as fast as they can. That said, ocean concentrations can be at least a very rough guide to whether trace elements measured by ICP may be too low or too high.

All of these thoughts are just my opinion, and I recognize that others have divergent opinions on what should be done about trace elements. I welcome any discussions, corrections, clarifications, or differences of opinion in the thread that is associated with this article.

Since the table may not read well on all devices, i have attached the table as a pdf as well.

Happy Reefing!

Thank you Randy. I see the images by not the PDFs to download?

 

[Marc Pardon]

Thanx for the interesting write-up! You leave a questionmark at Fluoride. Any idea how we can dose this and keep a certain level? I have tried with Sodiumfluoride to get to NSW-level and had negative effects on my Acropora. It looks that they get irritated and show some signs of STN. The other thing is it gets "depleted" very fast :

https://web.archive.org/web/20030101180144/www.animalnetwork.com/fish2/aqfm/2000/jan/bio/default.asp

An article by Craig Bingman about Fluoride depletion in four reeftanks.

 

[Outlaw Corals]

Molybdenum is pink for "not recommended" but then says "yes, critical for many..."?

Kalium is for pink and red

 

[Outlaw Corals]

I just started dosing trace elements a few days ago, I’m dosing strontium, kalium, iron and fluorine along with the micro e elements all by Aquaforest

 

[Randy Holmes-Farley]

@Randy Holmes-Farley Is your cobalt concentration of 6 ng/L intentional? I typically see NSW concentrations on the magnitude of 0.Xμg/L or 0.0Xμg/l referenced, 0.006μg/L seems very low.

Since I seem to have lost the book that I took all of the concentrations from (years ago), this is a good place to reiterate and show data of how overly simplified it would be to give a single concentration for a trace element. These are also not target levels, but natural ocean levels.

In this article from 2022, we see in Figure 2a that the cobalt concentration is very low at the surface, rises with depth to a peak at about 500 meters deep, then drops back and levels out for all depths lower than about 2,000 meters. We can also see in Figure 3 that the concentrations and the depth profile vary greatly from location to location.

Major processes of the dissolved cobalt cycle in the North and equatorial Pacific Ocean

Major processes of the dissolved cobalt cycle in the North and equatorial Pacific Ocean

Abstract. Over the past decade, the GEOTRACES and wider trace metal geochemical community has made substantial contributions towards constraining the marine cobalt (Co) cycle and its major biogeochemical processes. However, few Co speciation studies have been conducted in the North and...

bg.copernicus.org

"Dissolved Co was depleted in the surface Pacific Ocean (Fig. 5) due to phytoplankton uptake and utilization. The towfish samples, the surface-most samples collected for dCo around 2 m depth, typically represented a dCo minimum in the profile. Towfish dCo values were lowest in the North and South Pacific subtropical gyres, where average surface dCo reached near-zero values of 1.4 ± 2 pM (n=10) and 0.7 ± 2 pM (n=5), respectively"

A value of 1 pM equates to a weight concentration of 59 pg/L or 0.06 ng/L or 0.00006 ug/L

" The surface dCo values were comparatively larger in the North Pacific subpolar gyre and equatorial Pacific, with average surface dCo values of 50 ± 31 pM (n=5) and 8 ± 8 pM (n=10), respectively."

The average of the depth profile shown in Figure 2 is about 35 pM, which corresponds to 2,065 pg/L = 2.1 ng/L = 0.002 ug/L. A value of 8 pM for equatorial pacific surface water gives 0.0005 ug/L.

Thus, the value I give in the article of 6 ng/L is actually lower than surface equatorial pacific, and is closer to but still lower than the values found in the bulk of the depths of the ocean.

 

[gws3]

@Randy Holmes-Farley Would you mind telling me what your recommended dosing strategy then? These levels are much lower than ICP-MS detectability. I can't speak to other salts, but my Oceamo ICP-MS results for Instant Ocean range from 0.02 to 0.04 ppb Cobalt. This makes me think that even infrequent water changes would likely be sufficient for maintaining Colbalt.

 

[Randy Holmes-Farley]

@Randy Holmes-Farley Would you mind telling me what your recommended dosing strategy then? These levels are much lower than ICP-MS detectability. I can't speak to other salts, but my Oceamo ICP-MS results for Instant Ocean range from 0.02 to 0.04 ppb Cobalt. This makes me think that even infrequent water changes would likely be sufficient for maintaining Colbalt.

That is a conundrum for many trace elements. How much is enough or what chemical form for which organisms? And how much is too much?

I never intentionally dosed cobalt. I don't know if anything suffered, nor do I know an exact value since Triton detected none with a limit of detection of 0.4 ug/L (at least at the time).

It may have been plenty, or the tank may have done better with more.

That brings up the previous article comments, and the trial and error dosing to see if it is actually helpful may be the best bet for things whose natural abundance in below detection limits:


Many folks dose trace elements to try to replace those lost in the aquarium, and there are many commercial mixes and DIY recipes. Deciding how much of what to dose is a vexing problem that may be best answered by trial and error (which successfully deals with all of the uncertainties described above) but it takes a lot of time and effort. Folks attempt to shortchange that effort, with a number of different methods that try to eliminate some of the uncertainties, and I’ll describe the pros and cons of these below.

A. Some commercial trace element mixes are designed to be used in a volume dosed per day or week methodology. For example: Add 1 ml of solution to each 100 L of aquarium water daily. Certainly the easiest way for the reefkeeper, but they can only be “perfect” for a single type of reef tank. That said, they may be adequate for a reasonably wide range of reef tanks. A beginning reefer might start here with an additive from a company they have confidence in, since the reefkeeper is fully trusting them to get it right, and IMO, not all companies have earned such trust. One might consider experimenting with lower or higher doses over time to better match the actual needs of your aquarium, and might start high or low if there is more or less growth in general in the aquarium relative to an average tank. A new reef tank with few organisms will certainly take up fewer trace elements, and more is not necessarily better.

B. A second approach ties the amount of trace elements added to the calcification rate. Say, to alkalinity demand per day or calcium demand per day. For example: Add 1ml of supplement for every 20ppm of calcium added per 100 liters of aquarium water. The company makes some sort of determination of the amount of trace elements needed per unit of calcification for a typical reef tank. A number of products do this either explicitly (for a trace supplement) or implicitly, such as with a two part or one part alkalinity and calcium method that has extra added trace elements.
The calcification rate would be a reasonable approach if the tank has about the same consumption characteristics as the tank the product was designed for, but what if it doesn’t? An entirely soft coral tank with a macroalgae refugium and organic carbon dosing may consume more trace elements than a hard coral tank that uses none of these methods. Yet the hard coral tank has far higher calcification and hence is getting more trace elements. This method likely works out for many tanks, but if your tank deviates from a typical mixed tank that the product was likely designed for, it may be a suboptimal way to dose. Again, trust of the company also comes into play. If the method is a stand-alone trace element mix, one might experiment with doses as described in A.

C. A third approach involves testing of the concentrations of many trace elements by ICP (the only way generally available to reefers to test trace elements at low concentrations) and dosing each element measured to bring it back into a desirable range. This method is more expensive and labor intensive than A or B, but is clearly better, in my opinion, without being perfect. The issues include the accuracy of the ICP measurement (may be partly determined by the company and their protocols, partly by the exact type of ICP used, and partly by what happens to the sample between your tank and the plasma itself. Freezing, bacterial growth in the sample tube, binding to the tube sides, any sort of filtration or centrifugation, or lack thereof, at the company may all play a role in the accuracy. Additionally, the issues of chemical speciation (e.g., ferrous vs ferric iron) and complexation by organics is not resolved by ICP. Finally, desirable ranges are often determined by one or more people that may or may not have the same focus (color vs growth, different organisms considered, etc.). I’m also wary of some of these methods that suggest dosing of chemicals not known by science to play any role in any known organisms. If using such a method, I’d either leave these out, or at least experiment by not dosing them and see if anything is different in my aquarium.

 

[Spare time]

I'm suprised by arsenic. I'd imagine it would be dangerous to dose.

 

[Randy Holmes-Farley]

I'm suprised by arsenic. I'd imagine it would be dangerous to dose.

Like copper, yes, but much less clearly needed. Hence listed as experimental.

I considered saying no, and I personally would not bother to experiment with it, but I cannot rule it out as useful in some contexts.

Wikipedia has a summary of known biological roles (beyond toxicity):

Arsenic - Wikipedia

en.wikipedia.org

 

[Harpo]

I dont see the pdf. Thanks for posting this.

 

[Randy Holmes-Farley]

Thanx for the interesting write-up! You leave a questionmark at Fluoride. Any idea how we can dose this and keep a certain level? I have tried with Sodiumfluoride to get to NSW-level and had negative effects on my Acropora. It looks that they get irritated and show some signs of STN. The other thing is it gets "depleted" very fast :

https://web.archive.org/web/20030101180144/www.animalnetwork.com/fish2/aqfm/2000/jan/bio/default.asp

An article by Craig Bingman about Fluoride depletion in four reeftanks.

I do remember Craig's article. I cannot see any chemical better for dosing fluoride than sodium fluoride, perhaps at higher dilution before adding it.

I don't know that I would conclude it typically gets depleted very fast. Is that what you observed? Plenty of folks not dosing it see fluoride at some level. The Triton test I used years ago did not check it.

 

[Randy Holmes-Farley]

Thank you Randy. I see the images by not the PDFs to download?

To be honest, I might be messing it up somehow. It is attached to the article, but I too do not see it as able to be downloaded. Maybe one cannot attach pdf's to articles. I'll try here. Can you see it here?

 

[paparoof]

To be honest, I might be messing it up somehow. It is attached tot eh article, but I too do not see it as able to be downloaded. Maybe one cannot attach pdf's to articles. I'll try here. Can you see it here?

Yes.

And thank you for doing this.

 

[PensacolaReefKeeper]

In a previous article I discussed my thoughts on trace elements

Randy's thoughts on trace elements

Randy's thoughts on trace elements in reef aquaria.

www.reef2reef.com

This article expands on that discussion by providing specific guidance for all elements one might dose.

First, some explanation.

I have listed many elements as not recommended to dose based on the lack of evidence of a requirement in ANY known organism. These are shown in a lavender color on the table below. I see no rationale to dose these, despite many being at odds with recommendations that permeate the reefing community. In many cases those recommendations may stem from the false assumption that if a coral skeleton deposits an element, it must be useful for the coral. That assumption is just not true. Precipitating calcium carbonate incorporates all sorts of elements from seawater that have no benefit, up to and including uranium. Barium seems to fit that idea, and I reject the idea that it is needed or useful. Also colored in lavender are a few elements that are only known to be used by a single microorganism that is unlikely to be important in any reef tank, and they drop off the dosing list. Cadmium is such an example.

Second, just because I recommend an element DOES NOT mean I agree with the wide ranging claims for those elements. I do not believe strontium is useful for hard corals, for example, but it does have uses in other organisms and makes the dosing list. Likewise, I do not believe shrimp need iodine, but it makes the dosing list because it is used by other organisms such as some gorgonia.

Third, some elements may be required by some or even many organisms but also may have the potential for toxicity if overdosed and one needs to be very careful dosing these. These elements include copper and arsenic.

Finally, some elements lack much info on what happens if they are not maintained at all, and these I have put in the experiment category, even if there are organisms somewhere known to use then. Fluoride, arsenic, tin, and tungsten fit this category.

Recommendations

Before getting to anything else, note that a yes for dosing in the table below does not mean it needs to be dosed in all tanks. It means that it may be needed if levels are sufficiently low. I do not recommend individual random dosing without measurement except for iron, manganese and silicate that are all rapidly depleted and show little harm from overdosing. That said, dosing certain commercial trace element mixes without measurement may be acceptable depending on the system and the reliability of the company providing the solution and dosing guidelines.

The table below recommends dosing a variety of major ions as needed (e.g., potassium, calcium, magnesium, etc.), but those are not the point of this article. Two elements (N as nitrate and P as phosphate) also make the list to maintain, and sometimes are considered trace elements, but are not the main focus of this article.

Two trace elements warrant special attention since they rapidly deplete and are used by a great many organisms: iron and manganese. If you dose no other trace elements, these two would be the two I'd pick.

I recommend silicate dosing if you care about either sponges, or the ability of diatoms to displace more problematic pests from surfaces such as rocks.

There are a number of other trace elements that are very important for organisms (e.g., vanadium). Whether these get low enough to warrant dosing may be system dependent, and reefers lack good info on what levels are too low for any given organism we keep, but it is not hard to maintain detectable levels and/or look for biological effects when dosing.

I'm sure many folks will be disappointed that I am not providing a specific concentration target or range for each element. The reason I do not, even when others do so, is because I do not think there is sufficient data to make such recommendations. Even recommending natural levels is fraught with problems. This is why:

1. Accurate measurement of trace elements is not assured even by using and type of ICP. Proper procedures need to be followed, and we rarely have such info.

2. The chemical form present in an aquarium greatly impacts it bioavailability and toxicity. These chemical forms can include oxidation states (e.g., iodide and iodate for iodine) and in the binding of the elements by organic matter (e.g., copper is known to be nearly completely bound by organics in the ocean, significantly reducing its toxicity relative to bare copper ion.

3. Reef hobbyists keep a very wide range of organisms. if someone suggests a particular target concentration for a trace element, what organism is that based on? Do you even keep that organism?

4. Even knowing the chemical form of trace element in a reef tank (we do not) and somehow matching it to the ocean concentration (where and at what depth), the ocean itself may not be optimal. Iron is known to be limiting to the growth of some organisms in the ocean. Do we want to have that same limitation, or not?

To this end, I provide the whole ocean average concentration in the table below. Trace elements vary by depth and by location. Iron and silicate, for example, are greatly depleted in surface water relative to deeper water because of organisms grabbing them up as fast as they can. That said, ocean concentrations can be at least a very rough guide to whether trace elements measured by ICP may be too low or too high.

All of these thoughts are just my opinion, and I recognize that others have divergent opinions on what should be done about trace elements. I welcome any discussions, corrections, clarifications, or differences of opinion in the thread that is associated with this article.

Since the table may not read well on all devices, i have attached the table as a pdf as well.

Happy Reefing!

Makes me really wish all for reef had iron and potassium....