trace Elements?

[drsyme]

Are they necessary? Are they a waste?

My tank is just over three months old. 110 gallon total system volume, 105 lbs LR. 2 clown fish, 1 royal gramma, 1 scopus tang, 1 pj cardinal.

a starburst polyp, zoanthid colony, and mushroom rock

didadema urchin, 2 starfish, 3 brittle stars, astrea, cerith, and nassarid snails, some red and blue legged hermit crabs.

Lots of corraline algae growth, some halimeda and one persistent spot of cyano.

Edit: I should also say that I do 5% water changes weekly using IO or Reef Crystals.

[TheReefer12]

Depending on what you keep in the tank, you may need trace elements IMO. I know some corals need trace elements present. You only need to add it once every two weeks.

[tdwyatt]

Originally Posted by TheReefer12

Depending on what you keep in the tank, you may need trace elements IMO. I know some corals need trace elements present. You only need to add it once every two weeks.

nope, there is a reason they are called trace elements. Check the James Millero text for reference, but the rate of use for the majority of the tracelements is so low that most corals only include them in there skeleton at the same ratio as they are present in the water column, and are NOT rate limiting for growth. Although many organisms do use the trace elements, they are not rate limiting at seawater concentrations for the ornamental corals we keep. Maintaining a good water change schedule is all that is needed to maintain these levels as those of NSW, additional supplementation is not needed. This is especially true if coral systems use a CO2 driven Aragonite reactor for the Ca and alk supplements, as the coral skeletons dissolving supply any potential need for supplementation along with whatever is available in the water changes.


The equivalent of 10% water changes every two weeks is sufficient to replenish trace elements in closed systems if you use a good ASW mix like IO, Reef Crystals, Kent, etc. Biggest problem is accumulation of many of the minor and trace element metals that have no animal or exportable sinks. This requires that we make a once a year large water change to export a goodly portion of these substances, along with occasional use of adsorbants like GAC or the resins like Purigen, etc.


As there are few accurate hobby level tests for most of what the Hobby manufacturers push as "absolutely necessary for good coral growth and color", there are few means of accurately monitoring what levels end up in the tank as they are dosed into the systems. This may lead to unexplained failure to thrive, as many of the trace elements can become toxic agents as their level in the water column rises above normal levels (think Cu, Sr, Ar, Pb, Zn, Hg, Cd...)


Basis for determining how the trace elements are classified is based on concentration in seawater (NSW):

• Major elements . . . . 0.05 to 750 mM
• Minor elements . . . . 0.05 to 50 mcM
• trace elements . . . . 0.05 to 50 nM

developed with tabulations by Bruland at the Univ of California at Santa Cruz using NWS at 35 PPT salinity.

Most of the trace elements are metals, and are divided into three major groups based on their electron shell configuration. First of these is the d^0 cations, which are primarily in the rare gas configuration and form few complexes, usually with Floride (there is little evidence to suggest that these cations form complexes with hevier halides) or as ligands with oxygen as the donor atom for electrons (such as sulfate, carbonate or phosphate)

The second group is the d^10 cations, which have an outer shell of 18 electrons, so will include Ag, Zn, Ga, and Sc. These will be univalent cations and will react much differently than the D^0 (typo: edit from d^10-tdwyatt) cations, forming very strong complexes with the halides approaching covalent bond strength, usually as either the chloride or floride salts in seawater (and are very soluble as such, although some may exist primarily as hydroxides based on atomic size Vs. low concentration issues.)



The third group are the transitiion metals between d^0 and d^10 in which the d shell electrons are more than zero but less than 10. Solubilities of each metal complex have been stidied extensively, and as a result, the "Irving-Williams order" of solubilities has been developoed*. These metals include Mn, Fe, Co, Ni, Cu, and Zn.



The amounts of many of the trace elements are still relatively high compared to their biological rate of use, and the type of distribution in seawater, whether it be conservative, a nutrient distribution, subject to surface depletion and depth recycling, or depleted at depth still demonstrates little chance of depletion based on seawater concentrations***. For more information, see the Millero text on page 119 for a chart of the differing types of distributioin in seawater and some rates of depletion. Although these are not always reflected in closed systesm (we have neither the depth nor the biologicl cycles that complete these distributionsA), they do reflect the limited uptke and rate of uptake for the nutrients within rnges that we can easily replace with regular water changes as already suggested. Anything else is both overkill and wasteful. I don't like to use personal experiences to support any such claim, but I have NOT SUPPLEMENTED TRACE ELEMENTS directly since the second round of the major ASW mixes have become available (it was dirrerent back when you had to make your ASW mixes...)




HTH









[i]*see Irving-Williams order, electron configs, and solubilities associated with this order

** see this link on some distribution models of nutrients in seawater

***notable exceptions would be surface issues in the ocean with silicon, phosphate,Iron, and cobalt under various algal bloom conditions




HTH

[drsyme]

Originally Posted by tdwyatt

nope, there is a reason they are called trace elements. Check the James Millero text for reference, but the rate of use for the majority of the tracelements is so low that most corals only include them in there skeleton at the same ratio as they are present in the water column, and are NOT rate limiting for growth. Although many organisms do use the trace elements, they are not rate limiting at seawater concentrations for the ornamental corals we keep. Maintaining a good water change schedule is all that is needed to maintain these levels as those of NSW, additional supplementation is not needed. This is especially true if coral systems use a CO2 driven Aragonite reactor for the Ca and alk supplements, as the coral skeletons dissolving supply any potential need for supplementation along with whatever is available in the water changes.


The equivalent of 10% water changes every two weeks is sufficient to replenish trace elements in closed systems if you use a good ASW mix like IO, Reef Crystals, Kent, etc. Biggest problem is accumulation of many of the minor and trace element metals that have no animal or exportable sinks. This requires that we make a once a year large water change to export a goodly portion of these substances, along with occasional use of adsorbants like GAC or the resins like Purigen, etc.

As there are few accurate hobby level tests for most of what the Hobby manufacturers push as "absolutely necessary for good coral growth and color", there are few means of accurately monitoring what levels end up in the tank as they are dosed into the systems. This may lead to unexplained failure to thrive, as many of the trace elements can become toxic agents as their level in the water column rises above normal levels (think Cu, Sr, Ar, Pb, Zn, Hg, Cd...)


Basis for determining how the trace elements are classified is based on concentration in seawater (NSW):

• Major elements . . . . 0.05 to 750 mM
• Minor elements . . . . 0.05 to 50 mcM
• trace elements . . . . 0.05 to 50 nM

developed with tabulations by Bruland at the Univ of California at Santa Cruz using NWS at 35 PPT salinity.

Most of the trace elements are metals, and are divided into three major groups based on their electron shell configuration. First of these is the d^0 cations, which are primarily in the rare gas configuration and form few complexes, usually with Floride (there is little evidence to suggest that these cations form complexes with hevier halides) or as ligands with oxygen as the donor atom for electrons (such as sulfate, carbonate or phosphate)

The second group is the d^10 cations, which have an outer shell of 18 electrons, so will include Ag, Zn, Ga, and Sc. These will be univalent cations and will react much differently than the D^10 cations, forming very strong complexes with the halides approaching covalent bond strength, usually as either the chloride or floride salts in seawater (and are very soluble as such, although some may exist primarily as hydroxides based on atomic size Vs. low concentration issues.)

The third group are the transitiion metals between d^0 and d^10 in which the d shell electrons are more than zero but less than 10. Solubilities of each metal complex have been stidied extensively, and as a result, the "Irving-Williams order" of solubilities has been developoed*. These metals include Mn, Fe, Co, Ni, Cu, and Zn.

The amounts of many of the trace elements are still relatively high compared to their biological rate of use, and the type of distribution in seawater, whether it be conservative, a nutrient distribution, subject to surface depletion and depth recycling, or depleted at depth still demonstrates little chance of depletion based on seawater concentrations***. For more information, see the Millero text on page 119 for a chart of the differing types of distributioin in seawater and some rates of depletion. Although these are not always reflected in closed systesm (we have neither the depth nor the biologicl cycles that complete these distributionsA), they do reflect the limited uptke and rate of uptake for the nutrients within rnges that we can easily replace with regular water changes as already suggested.


Anything else is both overkill and wasteful. I don't like to use personal experiences to support any such claim, but I have NOT SUPPLEMENTED TRACE ELEMENTS directly since the second round of the major ASW mixes have become available (it was dirrerent back when you had to make your ASW mixes...)


HTH




*see Irving-Williams order, electron configs, and solubilities associated with this order

** see this link on some distribution models of nutrients in seawater

***notable exceptions would be surface issues in the ocean with silicon, phosphate,Iron, and cobalt under various algal bloom conditions




HTH

yea, thats what I thought.

[BigDaddy]

wow. I guess I couldn have spent my 10 bucks somewhere else. Cant believe I didnt realize that! It's so obvious

[drsyme]

"wow. I guess I couldn have spent my 10 bucks somewhere else. Cant believe I didnt realize that! It's so obvious

---

i am always right 80% of the time. "






It is always that **** 20% that bites you in the ass.