Iodine?

O.k. there is always a debate about dosing Iodine. Upon researching activated carbon, I kept seeing the term "Iodine number", this is used to indicate the quality or absorption capability of the carbon. Here is an excerpt;
[edit] Properties of activated carbon


[edit] Iodine Number

Many carbons preferentially adsorb small molecules. Iodine number is the most fundamental parameter used to characterize activated carbon performance. It is a measure of activity level (higher number indicates higher degree of activation), often reported in mg/g (typical range 500-1200 mg/g). It is a measure of the micro-pore content of the activated carbon (0 to 20 Å, or up to 2 nm) by adsorption of iodine from solution. It is equivalent to surface area of carbon between 900 m²/g and 1100 m²/g. It is the standard measure for liquid phase applications.
Iodine number is defined as the milligrams of iodine adsorbed by one gram of carbon when the iodine concentration in the residual filtrate is 0.02 normal. Basically, iodine number is a measure of the iodine adsorbed in the pores and, as such, is an indication of the pore volume available in the activated carbon of interest. Typically, water treatment carbons have iodine numbers ranging from 600 to 1100. Frequently, this parameter is used to determine the degree of exhaustion of a carbon in use. However, this practice should be viewed with caution as chemical interactions with the adsorb-ate may affect the iodine uptake giving false results. Thus, the use of iodine number as a measure of the degree of exhaustion of a carbon bed can only be recommended if it has been shown to be free of chemical interactions with adsorb-ates and if an experimental correlation between iodine number and the degree of exhaustion has been determined for the particular application.

Sooo, my question is, how much Iodine is being absorbed by the carbon we use and isn't this a reason to test for and dose Iodine?

 

I'm not really sure. Would have to test it by measuring your iodine before and after... but to be safe, maybe its best to time your carbon use so its used just before a water change to ensure an adequate amount of iodine is replenished back into the sytem?

I would also imagine that this number, even though having the word iodine, refers to the carbons overall ability to absorb these different trace elements? So I would imagine that iodine is not the only element effected by carbon use. Regardless, I have never seen an ill effect from carbon use, despite others admitting so.

 

I belive the benefits of carbon outweigh testing/adding iodine. Unless you know for sure your tank is low, you really shouldn't dose. It's one of those things that when used improperly can mess up a tank very quickly. Add more than your tank needs and you'll see green grow FAST and your critters(fish and corals) tend to freak out!:-/

 

I think what he's saying is that if you're actively running a carbon with a high Iodine number, it might be a good idea to test it and dose, if needed.

Yes, overdosing on Iodine can be dangerous. You also need to know if you're dosing Elemental Iodine, Iodide, or Iodate. Microalgaes and Macroalgaes are the biggest sinks for Iodine. Many sponges and some gorgonians and Xeniids are as well.