I'm aware that table salt has additives such as iodine. I think I might have mentioned that up above somewhere....
(The following section comes from
The Skeptical Aquarist I would definitely recommend reading the whole article)
"Fears about toxicity of the iodine represented in table salt are still often expressed in warnings not to use iodized salt in the aquarium. Potassium iodide (sometimes it's sodium iodide) in U.S. iodized table salt ranges from 20 to 40 parts per million. So what part per million of iodide does that potassium iodide represent?
I'm innumerative. The ppm iodide were worked out by aquariaddictus in a thread at AquariaCentral, started 1 March 2003 (you can find it at AC: search "iodized salt ppm iodide"). Aquariaddictus pointed out that there is no elemental iodine in KI, just as there is no free chlorine in table salt. Iodide is I-, while iodine is I2, as chloride is Cl- while chlorine is Cl2. The terms aren't interchangable.
Potassium is number 19 on the periodic table, Iodine is number 53. So pure KI is 73% iodide. Thus the iodide in the potassium iodide additive is between 14.6 - 29.2 ppm in the dry salt.
KI weighs 15.38 grams per teaspoon. So, 15.38 grams/one teaspoon per gallon = 15.38 grams per 3.7854 liters = 4 ppm as KI. If you add iodized salt at the rate of one teaspoon per gallon, you are adding iodide in the range of 0.083 - 0.166ppm.
After laying out the calculations, aquariaddictus remarked, "All in all, I have to believe it's a drop in the bucket. Does anyone use a tablespoon/gallon except in times of severe disease?""
There's my support for my statement that the amount of iodine (or any other additive) is in such small quantities, that it doesn't matter.
~JW