Firstly - Shrimp NEED iodine to help them through their molting processes.
Secondly - Doing 10-15% weekly/bi-weekly water changes should keep your iodine at a good level without adding iodine seperately.
Thirdly - Adding iodine can cause your shrimp to molt prematurely. Which means they'll age faster and ultimately die much quicker than they should.
Fourthly - Some advice from me... I used to be a
[hr]
doser... I bought like every type of mineral additive out there and used them according to their label. Recently I decided to STOP doing any dosing besides calcium/buffer when needed and doing 10% bi-weekly and sometimes weekly water changes..
The results --- Dosing like crazy ended up doing NOTHING for my tank. I noticed no real improvements other than normal growth.
Weekly/bi-weekly water changes have kept everything perfect, everything grows well, and its far less hassle than adding everything.