Importance of Iodine? - Chemistry Science Fiction

[Garf]

Seachem iodine test update - found a few threads on reef central from way back, saying the powder reagent needing mixing up, but the formulae had somehow been modified to correct this. Anyhow, mixed the powder after another test kit read zilch. And as if by magic, it worked. Just for info, my new saltwater is identical to my tank dosing 1 drop of Lugol's in 60 gallon SPS tank, daily. I suppose I better break out the potassium test kit.

 

[taricha]

Seachem iodine test update - found a few threads on reef central from way back, saying the powder reagent needing mixing up, but the formulae had somehow been modified to correct this. Anyhow, mixed the powder after another test kit read zilch. And as if by magic, it worked.

Gonna ask some follow up Qs to help me unpack your info here.

so the seachem iodide kit powder sometimes needs mixing up to work? And then it can detect lugol's Iodine which is a mix of Iodide, I- (as KI) and Iodine I2. Does it detect the I2 in lugol's during the intermediate step 3? Or only at the end (step 5) when iodide is detected?

Just for info, my new saltwater is identical to my tank dosing 1 drop of Lugol's in 60 gallon SPS tank, daily.

So your new salt mixed water has a measurable iodide level (I also find my Instant ocean has plenty of Iodine), and your tank water getting one drop of lugol's per 60 gal per day also has about the same measurable iodide level?

(one testing blind spot here is that as the tank is converting your lugol's I2 to I- to iodate IO3, then the seachem test kit will not see it. So depending on how the Iodine speciation works out in practice - there may end up being a lot of iodate, IO3 in your tank and you only measure a tiny amount of iodide I-)

I suppose I better break out the potassium test kit.

K? what's that about?

 

[Garf]

Does it detect the I2 in lugol's during the intermediate step

Nothing showed up. I've been adding it to my waterchange water that's slowly dripped into the tank and it doesn't show up there either.

K? what's that about?

Am I not adding potassium in the Lugol's? I made an assumption I was, but now you've got me wondering, lol. I've only used the potassium kit a couple of times ever because it's a pain in the neck, from memory.

 

[taricha]

Am I not adding potassium in the Lugol's?

Oh right. Yes. I missed that connection.

lugol's Iodine which is a mix of Iodide, I- (as KI) and Iodine I2.

Hopefully you are adding small fractions of a ppm of Iodine (as KI) which will make the K addition totally undetectable.