First off, don't add anything without testing it first. Adding iodine without checking the tanks current level is not a good idea. Second, the lighting could still be a possiblity depending on what kind of lights you have and how old the bulbs are. As bulbs age, the quality of light decreases. Also, increasing the lighting from what the corals were used to can affect them and take time for them to adjust.

Has anything else been added to the tank recently besides the Anthelia? Many corals can emit a mucous or toxin into the water that can affect the other corals. All corals and even fish react differently to things added to their environment. Water changes would help this, but it could be an ongoing problem. Also, the anthelia or any other recent addition could have been diseased or simply carrying a disease and that is affecting the zoos.

The other question is where is your water coming from? If it is your own RO/DI unit, when was the last time you replaced the cartridges or checked the water quality? Perhaps your water or even your Kalk mix was contaminated with something the zoos don't like.

Hopefully this will give you a few more things to check and perhaps some of the others on the forums may think of other things that could be an issue.