If it's iodine based it should be good enough to knock out the most common pests (flatworms, nudibranchs, red bugs, etc). Just make sure you dip them for at least five minutes and give it a good shake in the dip to dislodge and potential pests. It won't do anything for eggs though, and neither will just about any other dip - if the coral you're dipping is attached to a rock, plug, or has dead skeleton on it make sure you inspect those areas for eggs, usually miniscule gelatinous patches with barely visible dots in them.