Iodine - Iodide

NewbReefer

Reefing newb
I believe iodine changes to iodide shortly after it's introduced into the tank, correct me if im wrong. Well the other day i was at the LFS i beleive it was one of the Kent Marine Iodide supplements that on the back of the bottle that it said Iodine is toxic in certain amounts so is best to just dose with Iodide instead of Iodine? i have a trace elements bottle that has iodine so im wondering if i should not use that or get a Iodide supplement.
 
I can honestly tell you that in... ohhhh, say, four years, I have never even farted a thought of iodine in my tanks, let alone dose anything. whatever trace elements exist in the salt I use (I am a fan of premium salt mixes) seem to work for my tank. Just my :twocents:

-Doc
 
I can honestly tell you that in... ohhhh, say, four years, I have never even farted a thought of iodine in my tanks, let alone dose anything. whatever trace elements exist in the salt I use (I am a fan of premium salt mixes) seem to work for my tank. Just my :twocents:

-Doc


You use Oceanic right? I use Instant Ocean which i've been happy with but would like to start tryin some others once i use up my current bucket. Im not sure but swear i heard Iodine or Iodide is pretty important for inverts and lps and softies but yeah i don't think you need alot of it but i've heard dosing it can really help growth but i've also read somewhere that it has not yet been proven to be benificial.

fatman! I need, in simple terms please :), your thoughts and opinions on iodide and iodine, or anyone who knows anything about them or about dosing them. Im a bit of a newb when it comes to chemistry.
 
Inverts do need iodine. If you do weekly water changes you shouldn't have to add. I do test for iodine. A lot of others don't. I do add if my tank is very low.
 
I cannot speak to chemistry as one as enlightened as fatman. He is WAAAY smarter than I in that area. I know that the balance of trace elements in oceanic makes my corals grow and look healthy. Try oceanic after you are done with instant ocean and see what you think. It is worth the extra $7 in my book.

-Doc
 
I'll put Oceanic next on the list, do they make a reef salt like Instant Ocean? I wanna try instant ocean's reef crystal after Oceanic.

Thanks for that input Piggy. I'll probably get a iodine test kit to give me an idea of what brands of salt give me what i need as far as iodine goes.
 
I would say nearly no reefer who does weekly water changes that has not got a substantial number of corals in their tanks usually needs to supplement anything except possibly in their feeding regimen. If you do have a heavy coral load then things change. You then need to be concerned with calcium, calcium carbonate, magnesium and possibly strontium. If you are trying to export nutrients just through water changes and macro algae growth then iron supplementation should be considered. Iodine supplements are usually only an issue with inadequate water changes when you have lots Macro algae. If you are going to use iodine use Iodide and supplement daily. Take the monthly amount and divide the recommended dosage into a daily dosage. Google Randy Holmes-Farley Iodine, or that name and probably any supplement sold for reef usage and you can get the opinion of a chemist with a doctorates degree who is a reefer. He is spot on more often than not, but he is still just making educated assumptions in some areas just like others. For example he recommended Iodine for years and now in general for most home aquarium keepers he no longer recommends it.
Randy's latest opinion on Iodine:
I do not presently dose iodine to my aquarium, and do not recommend that others necessarily do so either. Iodine dosing is much more complicated than dosing other ions due to its substantial number of different naturally existing forms, the number of different forms that aquarists actually dose, the fact that all of these forms can interconvert in reef aquaria, and the fact that the available test kits detect only a subset of the total forms present. This complexity, coupled with the fact that no commonly kept reef aquarium species are known to require significant iodine, suggests that dosing is unnecessary and problematic.

For these reasons, I advise aquarists to NOT try to maintain a specific iodine concentration using supplementation and test kits.

Iodine in the ocean exists in a wide variety of forms, both organic and inorganic, and the iodine cycles between these various compounds are very complex and are still an area of active research. The nature of inorganic iodine in the oceans has been generally known for decades. The two predominate forms are iodate (IO3-) and iodide (I-). Together these two iodine species usually add up to about 0.06 ppm total iodine, but the reported values vary by a factor of about two. In surface seawater, iodate usually dominates, with typical values in the range of 0.04 to 0.06 ppm iodine. Likewise, iodide is usually present at lower concentrations, typically 0.01 to 0.02 ppm iodine.

Organic forms of iodine are any in which the iodine atom is covalently attached to a carbon atom, such as methyl iodide, CH3I. The concentrations of these organic forms (of which there are many different molecules) are only now becoming recognized by oceanographers. In some coastal areas, organic forms can comprise up to 40% of the total iodine, so many previous reports of negligible levels of organoiodine compounds may be incorrect.

The primary organisms in reef aquaria that "use" iodine, at least as far as are known in the scientific literature, are algae (both micro and macro). My experiments with Caulerpa racemosa and Chaetomorpha sp. suggest that iodide additions do not increase the growth rate of these macroalgae, which are commonly used in refugia.

Finally, for those interested in dosing iodine, I suggest that iodide is the most appropriate form for dosing. Iodide is more readily used by some organisms than is iodate, and it is detected by both currently available iodine test kits (Seachem and Salifert).


Oceanic is higher in calcium and lower in akalinity than Instant Ocean. Other than that they are pretty comparable. There is a good posting in the articles section on salt mixes.https://www.livingreefs.com/articles/marine-salt-mix-concentrations-t11776.php
 
Last edited:
Iodine can form any number of different iodides when added to an aquarium. There is also no known evidence other than some macroalgae storing a lot of it that has any use for it. If any inverts do by chance have iodides within their system, they surely did not just absorb it out of the water and would have to gain any such elements from the food they eat.
I have spent a great deal of time searching the science papers for anything related to iodides and inverts and could not find a single paper on it, even with algae, the only papers that mention it only state a given amount in the algae, not whats it for or if it is needed. Which makes me wonder how in the world this element came to be such a "needed' item in the hobby? Oh, and if you run carbon, you are most likely adsorbing it out of your system as fast as you are pouring it in.
This is the best article I have seen on Iodides and while a bit old, no new information that I am aware of has surfaced since it was written.
For a reef aquarium, calcium, magnesium and alkalinity are the only things that need to be supplemented, all other elements have no known uses or are of so little use there is no need to add them.

http://www.advancedaquarist.com/issues/mar2003/chem.htm

My Chemistry & Water Parameter Links

Chuck
 
You have to be pretty large or very commercial before the economics of not doing frequent water changes but doing suuplementals instead really should even be a question. Commercial outfits are een going to once through systems where a constant influx of new water is entering there tank systems with a constant flow being drained. Lots of small commercial coral growers do regular water changes of 25 to 50 percent per week with no supplements but Kalkwasser and calc reactors, if even that. Sometimes one has to take a step back and say is the newer better way really better, especially when it comes to water chemistry. It is that old saying that keeps returning. The solution to pollution is dilution. In the long run, when it comes to tank water, I prefer replacement to regeneration.
 
Back
Top