FAQs on Iodine Use, Supplements
Iodine in Marine Aquarium Systems
by Marco Lichtenberger, Marine System
Iodine 1, & FAQs on Iodine:
Testing/Test Kits, Sources of
Interactions, Troubleshooting/Fixing, & General Supplements, Calcium,
How and what they dose at the world's
largest reef system (CAS, Steinhart Aq. 2012)
Freshwater dipping new corals & coral frags
I have looked through Wet Web Media and have not been able to find a
complete answer to why dipping corals and frags in freshwater (RO/DI) is
<Too much stress; not worth it in trade-off of what one might get in
terms of lessening pests, parasites. Some slightly lower spg (a
thousandth or two) with the addition of iodide/ate, and possibly a
simple sugar (glucose or such... a hexose or pentose) IS>
I have seen statements that say to not do it on Wet Web Media, but I would
like to know the science behind the why.
<How much? Have you considered the use of a reference librarian... help
w/ a computer search bibliography? There's bits and pieces re these on
Thank you for your time!
<Welcome. Bob Fenner>
iodide dip/bath, for Scleractinians
I ran out of Seachem Iodine and LFS has no more so I picked up a bottle
of Brightwell Aquatics Lugol's solution, upon reading I see that
the concentration is 3750mg/oz 126,803 ppm (!!) and each drop will
increase iodine by 1,7ppm / gallon. If I want to make a
dip/bath for helping coral to recover (stopping RTN and STN) How many
drops should I add to how much water? I don't want to overdose as it's a
very high concentration.
thanks in advance :D
<Mmm, yes; and though I'm not a giant fan of this format of iodine and
potassium iodide... as a supplement, it can/will work for this
disinfectant purpose. IF this were a commercial setting, I'd not worry
re much at all re actual dosing (in practice I/we really just "squirt it
in the transit volume/acclimation container", likely w/ a bucket of
freshwater (to lower spg, increase uptake), and a scoop of a simple
(hexose) sugar, like glucose... For home hobbyists, I might do something
similar, but a short time exposure to some elevated level of Lugol's
won't be harmful... I'd up the dosage to 3-5 drops per gallon for a
several minute bath. Bob Fenner>
Marco... would you consider penning an article for pay on
Iodine/ide/ate use in marine systems?
Your article on HPO4 sets the voice, standard. What say you?
<Thank you very much and no problem, will do. Marco.>
<Ah, good. BobF>
I've referred to your site many many times over the past years and
thank you for the valuable information.
I have a mature, five-year old saltwater tank. I've just recently
upgraded my lighting, enabling me to now support corals.
Since I have added the corals, I thought it would be wise to check on
the iodide level, wondering if I'd need to increase iodide
supplementation. (I was adding 5 ml Seachem Iodide on even days to my
110 gallon tank, which
resulted in .06 ppm iodide - perfect, right?)
<Yes... but I would add on a punctuated basis... perhaps once a week
after your water change regimen>
I couldn't get a valid reading from my Seachem test kit, so I
supposed that it had probably expired.
While shopping for a new kit, I ran across Salifert's version which
tests for iodide, iodine, and iodate. I ordered this one, and ran my
The good news is that I got the same .06 iodide reading, but the bad
news (I think) is that I got an off-the-charts iodate reading (>.2
<Happens... and one reason I encourage only periodic dosing of
I've read and re-read the information provided with the test kit
regarding iodide and iodate levels, but I can't seem to find a
definitive answer on what a high iodate reading really means, and which
of these elements (iodide, iodine, and iodate) our marine specimens
actually use. Salifert's web site does not have any additional
<Mmm, the valence state of Iodine changes to extents with local
chemistry, physical properties of the water; but often it is the
initial preponderance of one or t'other that results in such
There is one piece of interesting information in the test kit
instructions, under Interferences:
"The presence of strong reducing substances
<Mmm, yes... ORP, RedOx Potential... alters the valence
such as ascorbic acid will also give a false value. Some supplements
contain ascorbic acid."
<Mmm... I would not have put this statement in a circular... No
supplement has this much Vitamin C... This information is spurious,
More on this in a moment...
So, my question is, what do I really need to be testing (iodide or
iodate) and is this high level of iodate toxic?
<Really not generally an issue... Unless one is "really pouring
it in" in concentrated doses... Again, I would just do your
"normal dosing" once a week. Am sorry to state that I/we/WWM
has not produced a comprehensive set
of declarative statements (an article) re Iodine/ide/ate and its
practical use. The collection of FAQs re can be accessed here: http://wetwebmedia.com/ioddosingf.htm
and the linked files above.>
I perform 10% water changes biweekly (sometimes 5% weekly) along with
cleaning or changing the filter media (paper and carbon).
<The carbon will remove...>
I recently switched to Red Sea Pro salt, which greatly increased the
magnesium level (~1200 ppm now; was ~900 before), but do add a small
amount of mg and sr twice a week (Seachem Reef Advantage). I supplement
Seachem Reef Plus (Amino Acids and Vitamins) twice a week.
<Good products and good to stay with one manufacturer's
BTW - the first ingredient listed is ascorbic acid. And, as mentioned,
add 5 ml of Seachem Iodide every other day. I do not need to add
calcium - that usually tests between 450 - 500 ppm.
<I'd let slip into the 300's ppm range>
pH is 8.4; carbonate hardness is 10 dKH.
All of the coral look really healthy. For example, Zoanthid polyps are
all fully opened; xenia is growing very quickly and spreading up the
<Good. A much better guide/test than any colorimetric assay>
Thanks for your help. I'll be very interested in your thoughts
<Sorry to be so scant here. I am not trying to be disingenuous, but
I want to post "something" to the general public that is
simple, straight-forward, applicable... and w/o potential dire
consequence. Bob Fenner>