Iodide/Iodate/Iodine

reefer1 · Jun 8, 2015

When I test for Iodide/Iodate/Iodine using Salifert's test kit, I usually get negligible levels. I typically change 10% of my tank+sump water every 7-10 days.
Does this replenish the iodine?
Should I dose iodine?
If so, what brand do you recommend?
Thanks

KJ · Jun 8, 2015

Kent Marine Lugol's Solution.

Randy Holmes-Farley · Jun 8, 2015

That's a complicated question.

First, there's some iodine in new salt water, but if the goal is to maintain NSW levels, water changes will not suffice as it is depleted rapidly since algae and other creatures take it up.

Now the question is whether dosing it and maintaining natural levels is useful or desirable.

I dosed iodide for years, but then stopped as an experiment and nothing apparently changed. Many reefers have experienced that same effect.

My conclusions is that for most of the creatures we keep, it is an unnecessary activity. There are a few creatures, such as certain gorgonia, with a known need for iodine, but very few of the organisms we keep have a scientifically known need or use for iodine.

For that reason, I've not dosed it to my reef for at least a decade and do not think most people need to bother.

That said, it is easy enough for anyone to experiment and see if anything appears different on initiating (or stopping) dosing in their own reef.

If I were to dose, I'd dose iodide, not Lugols since Lugols contains a reactive and unnatural form of iodine (I2).

These have a lot more info:

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

http://www.advancedaquarist.com/issues/april2003/chem.htm

reefer1 · Jun 8, 2015

The articles were very informative. It seems that I shouldn't worry about it unless I have gorgonian or black corals, sponges, soft corals such as xenia, shrimp, or macro-algae. Even then, dosing may not be required (and perhaps can be harmful if an overdose occurs). These specimen seem to grow without dosing.
I can cross out one concern.
Thanks!

Randy Holmes-Farley · Jun 9, 2015

You're welcome.

Happy Reefing.

TheClark · Jun 9, 2015

Anecdotally, I can say that potassium iodide dosing helped my LPS quite a bit. It was no formal experiment but the only variable changed. LPS were expanded much more and just did better in general. I must have had some deficiency perhaps potassium or iodide...

Randy Holmes-Farley · Jun 9, 2015

Do you still dose it?

TheClark · Jun 9, 2015

I have stuck with it. Using the Salifert test to try and make sure it does not go too high.

Randy Holmes-Farley · Jun 9, 2015

Which types of LPS?

If you are sometime feeling experimental, you might stop dosing it for a bit and see if anything happens.

TheClark · Jun 9, 2015

Euphyllias showed the biggest expansion. Man, I would hate to stop at this point, but it is tempting in the name of reef science

Thanks Randy and Happy Reefing to you!

Oceansize · Jun 12, 2015

I've been wondering about this too. I read that iodine etc was important for the molting process, and since I have cleaner shrimp and quite a few hermit crabs, I've been dosing Lugol's upon my LFS owner's suggestion. My concern is that I have been following the dosing instructions to the letter and yet I never get an iodine or iodate reading from my Salifert test kit.

This made me concerned that the test kit may be to blame, but after removing a few cups of tank water, adding a drop of Lugol's and getting off the chart readings, I'm confident the kit is working.

Basically, I'm just curious if undetectable levels are something to worry about if I'm otherwise doing everything as instructed. The shrimps and hermits were molting normally at first, but not in awhile now. They certainly seem to be thriving despite this.

I don't know if this lack of detectable readings is normal or if my iodine uptake is really high and I should try upping the dose by an extra drop per week.

Randy Holmes-Farley · Jun 12, 2015

Shrimp do not need supplemental iodine, despite claims otherwise. Adding a lot of iodine may cause them to molt, perhaps trying to get rid of an undesirable compound.

FWIW, farmers raise shrimp around the world in aquaculture ponds and do not add iodine to it. And many reefers, myself included keep shrimp just fine without it.

Lack of a reading is normal as iodine depletes in a day or two in many tanks, from NSW levels to undetectable with a kit.

That said, your dosing is not likely hurting anything, and adding a bit more as an experiment is also not likely to hurt anything. So give it a try, if you want, and see if anything appears better.

beaslbob · Jun 12, 2015

is there any medical type effect on like rtn in sps corals?

Randy Holmes-Farley · Jun 13, 2015

If you dip them in a strong solution of Lugols you may kill bacteria that might be causing infections, but at the concentrations present in a reef tank it won't kill bacteria. The I2 added in Lugols also doesn't stay around long as it is quite reactive, and I- and IO3- (the natural forms of iodine in seawater) do not have an antibacterial property.