Trace elements

capman at capman at
Thu Sep 16 18:19:29 EDT 1999

>Hello everyone,
>    I wish to investigate the role of trace element depletion in closed-system
>aquaria as a possible limiting factor in the successful, long-term growth of
>Porites astreoides for bone graft material.  If anyone knows of any literature
>or the e-mail addresses of persons that may be helpful, I would greatly
>appreciate it.
>Robin Smith
>smithrt at

(The following response is sort of long...sorry about that).

Is your objective to study the trace-element issue per se, or are you
mostly interested in just figuring out how best to grow the corals?  I
don't personally know of good *controlled* studies regarding trace element
depletion in closed system reef aquaria, but I can point you in the
direction of *lots* of information on how to set up and maintain
closed-system aquaria to grow small-polyped stony corals, and I have become
quite successful with these corals myself.  Most of the available
information I am aware of comes *not* from good, controlled studies,
unfortunately, but from the more anecdotal experiences of amateur and
professional reef aquarists, who as a group have become quite skilled in
the art of maintaining thriving captive reef systems where most kinds of
soft and stony corals flourish.  Perhaps you already are a reef aquarist
and so are aware of this large body of information?  If not I can point you
in that direction and offer my opinions based on what has worked for me as
well.  For now though, a few comments on trace elements in closed system
aquaria and a few sources of information........

Regarding trace element depletion, most (all?) reef aquarists agree that a
variety of critical trace elements (including strontium and others) can
easily get depleted in closed system reef aquaria , but there is active
debate on how best to maintain trace elements at natural seawater levels in
reef aquaria.  Some successful reef aquarists dose iodine and/or strontium
on a regular basis, while others dose any number of different commercial
trace element mixes that include a wider variety of elements. Most likely,
some of the trace elements being added in these mixes are unnecessary, but
again, I don't believe good controlled studies have been done.....*someone
please correct me if I'm wrong* (I have read though that the formulation of
Combisan, which is one of these commercial mixes, was based on carefully
measured rates of trace element depletion in a reef tank in Germany).
Others feel that regular partial water changes using fresh synthetic
seawater is a perfectly viable (and in some people's minds preferable)
alternative.  Others do little or nothing intentional to manage trace
elements, and dissolution of sand as well as feeding of the fish in the
system probably replenishes some of the trace elements consumed by
organisms or lost through protein skimming.  The problem is that these
captive reef systems in which corals thrive are very complex with many
as-yet unquantified variables, and different aquarists have achieved geat
success using any number of different management approaches.  Quite likely,
what works in one reef aquarium may or may not work in another if other
aspects of setup and maintenance are different.

Many of these issues are frequently hashed out in the ReefKeepers mailing
list (Archived at which is
frequented by reef aquarists ranging from rank amateur beginners to highly
respected experts in reef tank husbandry and marine biology.  Also, many of
these issues are discussed in articles in Aquarium Frontiers online
magazine (  While certainly not a scientific
journal, Aquarium Frontiers is written at a much higher level than most
aquarium literature (some of Craig Bingman's articles are particularly
useful in the area of clarifying reef aquarium chemistry, and Craig would
probably be a useful person for you to contact).  There are also a number
of very good books on reef aquaria that have been published.  Though now a
little dated, The Reef Aquarium, Vol 1, by Delbeek and Sprung (Ricordea
Publishing, 1994) is a particularly useful book with an extensive

By the way, is there some reason you need to grow this particular species
of coral?  Would other SPS corals do?  I don't have first-hand experience
with Porites, but my strong impression is that some of the fastest-growing
SPS corals in aquaria are probably some of the Acropora species.   In
addition, to certain Acropora, Montipora digitata and Pocillopora
damicornis are other really fast growers in our reef system at Augsburg
College.  These particular SPS corals were recommended to me by Morgan
Lidster of Inland Aquatics in Terre Haute, Indiana (USA) when I asked him
what SPS corals might grow the fastest for use in student research
projects.  (Morgan propagates and grows corals for sale to reef aquarists,
and is a great source of practical information).

I hope this helps.  Let me know if I can help further.

**Also, if any readers of this message know of good references from the
scientific literature on this issue, I'd greatly appreciate hearing about
them as well.**


Bill Capman
Assistant Professor
Biology Department
Campus Box 117
Augsburg College
2211 Riverside Ave.
Minneapolis, MN 55454  USA
FAX: 612/330-1649
capman at

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