I was in the same situation a few months ago. My bottle never showed that it had iodine in it on the ingredients, but someone else showed me a newer bottle of it and it said it had iodine. I called tetra customer service and they said no iodine was present in their dechlorinator, so something didn't add up. I had to use it for another week until I got a different dechorlinator. There weren't any ill effects from it and I think honestly it's probably safe to use. Dechlorinator is dechlorinator isn't it? But I still switched. I use Seachem Prime now. It gives me a peace of mind knowing that there isn't any iodine in it, plus it lasts for ages.