Please perform a search on "iodine" here and you will get about a million answers as this issue has been discussed many times before. Especially read what I have written about it in my posts in an attempt to kill this iodine myth. In short...no iodine supplement is needed.
I have had crayfish, ghost shrimp, and cherry shrimp for over 12 months and I only used iodine once, 12 months ago. Then I stopped when I figured "If the iodine makes them molt, too many moltings too close together will kill them."
All my RCS have been breeding well for 5 months with no iodine at all.
to forget this wonderful function sometime , my bad 
