Iodine based dips are great. I use Tropic Marin's Pro Coral Cure. It gets rid of pests and hitchikers.
Lugol's is not commonly used as an additive, but works great as a dip.
Keep in mind, though, that most iodine based dip will cause coral to expel some zooxanthellae, which will temporarily reduce its coloration. Give it a couple weeks and they should be back to normal. The long term benefits faaaar outweigh the short term loss of color.