I also dose kent, using tech I right now and yes a skimmer removes iodine. Iodine helps prevent bleaching when changing bulbs and helps with blue and purple sps color, not a lot but some. If you are having stn issues then you need to test your water. What is you ph alk ca phos nitrates. You also need to keep an eye out for pests like AEFW. Strontium may help stn, it aids in keeping tissue attached to coral skeletons. It is always good to dose even a small amount of iodine (like a half dose) lps and softies also use it. Plus it is used up very quickly in a reef system.