You've for a long time have stood by the fact that zoas palys really don't do much with iodine that breaks up into iodide and iodate in the water column.
Yet any major zoa collector doses iodine and points to iodine as 1 of possibly the top 5 things to keeps zoas growing. Many go on to describe that iodide>iodide gets dosed to help with zia tissues. Without supplemental dosing iodine>iodide levels get stripped out by skimming.
Just wondering why you take this position
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Skimming? Iodide and iodate cannot be directly skimmed out. Why do you think they can be? Iodine is certainly incorporated into algae and some other organisms, possibly including skimmable whole microorganisms.
I do not rule out that supplemental "iodine" dosing has many effects, because people dose all sorts of different thangs that contain iodine, but may have effects for reasons unrelated to the iodine content. Lugols impacting trace elements, for example, by oxidizing them and changing their solubility and bioavailability. Someone "proving" that Lugols impacts their aquarium leaves unknown whether it has anything to do with the iodine or not. Same general idea would apply to the kelp product here since it contains lots of stuff.
I also do not rule out that iodine is useful for a small number of organisms, and that might extend to zooanthids, but my "expectation" is that it doesn't.
My position on iodine in general is for these reasons:
1. Many people, myself included, dosed iodine for years, and saw no difference when stopping. Perhaps normal foods suppy any "needed" iodine in these cases.
2. A variety of marine organisms have a scientifically known and published requirement for iodine (I detail what was known at the time in one of my iodine articles), but that does not include zooanthids. A quick search just now also didn't find any new data on this topic for zooanthids.
3. I have never seen any side by side experiment showing supplemental iodine has a clear benefit to most organisms we keep, even by hobbyists.
4. I haven't even seen clear cause and effect experiments in a single tank. That would involve no dosing for a while, stabilize the tank, then dose a purified iodide or iodate chemical and report the actual effect. Keep dosing for a while, let it stabilize, then stop the dosing and see if the initial effect disappeared. That level of experiment would help convince me, but is very rarely done. Most often folks just claim it helps (or not).
5. Cause and effect is far harder to demonstrate than most folks think. One or two or a dozen anecdotes do not do so. Zooanthid growers doing so is not convincing. it is cheaper to dose than test to see if it is working. Note how much controversy there currently is over whether the Biogen alzheimer's drug actually works. Showing something works is hard and time consuming and costly, and folks in the hobby very rarely do it.
That all said, dioine dosing is easy,a nd I typically recommend that folks try it for themselves if they aere interested,a nd jsut look with an unbiased eye to see if they "like" the effects (if any). if they do, there's little reason to not continue.
