Iodine/Iodide
Bob,
Thanks for the all the info. I don't believe there is a more complete and informative site on the web.
<Thank you my friend. We try>
This is a basic chemistry question, forgive my ignorance.
<We could start a club>
What is, if any, the relationship between Iodine and Iodide?
<An electron per... a difference in ionic charge... the actual supplied valence state in products?>
I recently purchased a Seachem test kit for the two of them as that the only way it came, with the understanding that I would be getting an Iodine reading. However, the kit has only Iodide reagents with natural sea water parameters for only Iodide, which are .06 mg/L.
I also must ask, contained in the body of instruction, they mention that ozone releases toxic free halides such as chlorine, iodine and bromine.
<Hmm... I really don't like this explanation... if there is iodide present perhaps....>
Why do they call iodine in this context a toxin? 
<Mmm, it actually is.... You may prompt me to get off my duff and write something in the way of a more complete "article" on this matter...>
I thought it to be a useful supplement.
<It is my friend... please don't be overly concerned here... this situation is a matter of human laxity/laziness re terminology... what people are actually supplying, the organisms using is largely iodide... but sloppily termed iodine (the element...)>
Am I getting a reading for concentrations of Iodine using this kit? If so, what are the concentrations I should be looking for?
<I should let the fine folks at Kent do their job here.... you are measuring iodide...>
Should it added to a reef with a few and stony soft corals and many mushrooms?
<Yes>
If so, should I supplement the tank or just rely on water changes which I make weekly. Thanks for you time.
Brett
<Better to best added per dosage requirements of the maker about once a week along with your water change schedule. Bob Fenner>

Iodine Test
Hey guys, I keep reading about how I need to make sure my iodine levels are correct but I don't seem to be able to find a test kit for it in my local pet stores. What exactly am I to look for? Thanks Robert
<Hey Robert, jump on over to one of the WetWebMedia.com sponsors and look at Seachem or Salifert test kits for iodine. You can jump to any WetWeb page and hit one of the links. Custom Aquatics, Foster and Smith, all have them. Craig> 

Iodine supplementation
Hello Crew, I'm confused about iodine supplementation.  
<Great... you're better off than I am: I have a much longer list of things that I'm confused about!>
I have various invertebrates and some turtle grass.  It's my understanding that iodine supplementation benefits both plants and inverts.
<Indeed... an essential trace element>
I recently bought Seachem Reef Iodide and a Salifert I2 test kit.  I originally tested my water and got nil for a reading.  So I added iodide as per directions.  After 12 hours, I tested again and got nil result.  So I repeated the procedure the next day.  Again, nil result.
<yep... not a big surprise either. Iodine lasts in most systems for about 6 hours. Hence the need in my opinion for small daily doses>  
I have since read that iodine ions "escape" the system readily and are not detectable after only a few hours.
<agreed... when dosed small and or in systems with good skimming, heavy bio-load and/or active chemical filtration>
If this is the case, what good is supplementing and it appears that the test is rather superfluous as well.  I think there's something I'm missing here. Thanks, Mike
<I'd begin with the manufacturers recommended daily dose and divide to daily doses. Use that for 2-4 weeks. If you do not see an increase in brown diatom algae, then you are not dosing too much. In time you can slightly increase the doses (and wait 2-4 weeks after each increment) by using diatom growth as an indicator for how much you can push the envelope. More is not better with Iodine, but daily is highly recommended in small daily doses IMO. Best regards, Anthony>

Interpretation Of Iodine Test Results...
Howdy.
<Hi there- Scott F. here today>
Dosing with Lugol's and had been using Salifert I2 test kit that is based on pink color of supernatant. That test never produced detectable iodine so bought new kit. New kit is much different (simpler, better?) and breaks out iodide, iodate, iodine. Instructions say that formation of precipitate with iodide test means concentration is greater than .2ppm. What is not clear to me is whether or not they mean if precipitate forms at 2-minute mark or if it forms at all. At 2 minutes, yellow color matches .04-.06ppm color chip. At 3 minutes, dark ppt forms. Are you familiar with this kit?
<I have used it in the past, but I do not have any recent experience with it. You bring up a good point...Not sure if the precipitate forms at the two or three minute mark...I would not assume anything, either.>
Does formation of ppt at 3 minutes mean that I need to back off dose? Salifert Web site is under construction and LFS is no help, Thanks, George.
<Well, George, what I might try is the "end run" to get hold of someone at Salifert that may have the knowledge of the workings of this kit...I'd talk to the LFS and find out what wholesaler they get the kits from, and-in turn, who supplies the wholesaler (hopefully, Salifert or their domestic sales reps). Yep- it has all the makings of a wild goose chase, but it may help you locate someone at the company who can help. In fact- here's an open call to any WWM reader that might know the answer to this question, as well....Regards, Scott F>

-Undetectable iodine and strontium levels?-
Thanks Kevin! Forgot to add that I do have an Aiptasia-friendly Lysmata amboinensis but no peppermint shrimp. How would peppermint shrimp get along with its tank mate?
<They'd get along fine and dandy>
When I looked when I got home this afternoon, I could not find the smallest of the Aiptasia. Do you think a snail or hermit crab found them?
<Doubtful, it may have gotten stepped on and retracted.>
I would think that feeding to support all snails and hermit crabs may be too close to over-feeding. Is it appropriate to feed for the fish and corals and let the chips fall where they may in terms of carrying capacity? I assume that means some shrimp and hermit crabs will become food for each other.
<You got it>
I have been testing and St and I have been almost undetectable.
<That's bizarre, I doubt that the tests are accurate.>
Have read that one may not want to add these nutrients or much else when fighting unwelcome inhabitants. Should I keep those levels up anyway for the sake of the animals I want to keep?
<If you are going to add anything, you should be testing for it. Since both of those levels are undetectable, you may want to verify with another quality test kit, because quite frankly I think they're dead wrong! Good luck! -Kevin>
Cheers, George.

-Low Sr. and Iodine-
Okay, maybe they are not undetectable but they are at the low end of the spectrum. Using Salifert test kits. <Very reputable> I guess my question is, should I go ahead and bring Sr and I concentrations up to what would be considered adequate or keep them low for now considering the presence of Aiptasia.
<If your goal is to best replicate NSW, I would keep these concentrations at NSW levels. Adding either of these chemicals shouldn't result in an increase in Aiptasia in the tank. Good luck! -Kevin>
Thanks again, George.

Tech - I from Kent Marine, and limpets 5/22/04
Good morning to all,
<and to you in kind>
Just a few questions for you, hopefully you can help. You usually have all the answers. I am curious if tech-I iodine supplement from Kent is okay to use. The label says it has free iodine. My test kit says it is a bad thing.
<somewhat subjective here. There seems to be two "camps" regarding advocacy of Lugol's strong iodine solution (the nutritive iodine of color/odor) versus clear Potassium Iodide solutions.  The other troubling thing is several keyhole limpets in my hospital tank. I believe both can be useful, both can indeed be abused/overdosed too. I favor Lugol's based solutions FWIW. I'm not a bog fan of some bottled supplements though... then ones that do not date their products for products with a definable lifespan/shelf-life. Iodine loses efficacy over time once mixed ion solution>
scoured WWM and have found two different opinions. Bob says okay and Anthony says they will eat soft coral flesh. I did find a big one sitting on my flower leather, so I pulled him off.
<some Limpet species are algae grazers, and some are predators on various reef invertebrates including corals (these tend to be the colorful ones with frilly/fleshy mantles). It depends on the species.)
Thank you for always being there for me and my tanks. Thanks,
Hopeless reef keeper- Daniel
<best of luck, Anthony>

Re: Chronic Fish Death
Well I've arranged to buy a 10 gallon to use as a quarantine from now on we'll separate new and sick fish.  I've decided it's well worth it.  So thanks for setting me straight on that.
As for iodine... Is there still iodine in water if we buy RO water?  Is there any way to test for toxic levels of iodine so that we may rule in or out that theory?
Sorry to pester you with so many follow-up questions. It's only because I find your information very helpful.
Lindsay
>>>Hey Lindsay,
It's no trouble!
You should be doing water changes once a month or so, and enough iodine should be present in the water. I can't remember off the top of my head if there are iodine test kits or not quite frankly. <There are. RMF>
For the moment, do your water changes as I said, and you shouldn't have to worry about it. If you do decide to begin adding iodine again, once a month would be plenty.
Cheers
Jim<<<