Iodine or Iodide?

[Leo73173]

Ok I want to know which is better and what is the difference and what better place to find out but here?

[ReeferAl]

Iodine, as in elemental iodine I2, is much more toxic to everything. Iodide is quite safe by comparison. Lugol's is a combination of iodine and iodide. Iodine can be converted in an aquarium to iodide I believe, and vice versa. If you dose Iodine you have to be much more careful to not overdose.

Allen

[ReeferAl]

A correction: Iodine can presumably be converted to iodide, but probably not the reverse. A third form of iodine, which is actually more abundant in sea water is iodate where the iodine atom is bound to 3 oxygen atoms. Both iodide and iodate are essentially non-toxic.

As far as I can tell, there is no advantage to I2 as an additive compared to iodide. Conversely, iodide has the advantage of being much safer. Some people will keep Lugol's on hand as a coral dip so for them the advantage might be that they only need to keep one form of iodine around. (Iodide has no value as a coral dip.)

The other question is, do you need to dose it at all. I'd recommend Randy H-F's articles on iodine here (http://www.advancedaquarist.com/issues/mar2003/chem.htm) and here (http://www.advancedaquarist.com/issues/april2003/chem.htm)

Allen

[Leo73173]

Hey thanks for the info

[davocean]

Usually not needed.
You can have plenty just by water changes.
Alot of people dose, and actually overdose, usually causing excessive molting in shrimp which leads to death.
If you can't test for it, don't add it.

[drummereef]

<a href=showthread.php?s=&postid=8950447#post8950447 target=_blank>Originally posted</a> by davocean
Usually not needed.
You can have plenty just by water changes.
Alot of people dose, and actually overdose, usually causing excessive molting in shrimp which leads to death.
If you can't test for it, don't add it.

Good advice. Always test before dosing anything.

[Leo73173]

Is that the same for calcium then?