Giesemann Iodine Test Kit

I use the Redsea, and Salifer iodine test!, this one has the best resolution!

Over the past couple of months, I've purchased and evaluated most of the hobbyist-level marine test kits from Red Sea, Salifert, Elos, Hanna, Nyos, SeaChem, Giesemann, Lamotte, and Hach, and then compared them to results from simultaneous water samples sent to Triton Labs for spectroscopy.Several manufacturers offer an iodine test kit. Iodine in seawater is present in multiple states and testing for one doesn't necessarily test for the others; it's fairly complicated and they all take slightly different approaches to the problem. Bottom line though is that NONE of the 4 hobbyist iodine test kits I've tried will provide anything like an accurate assessment of the iodine present in your tank. In a worse case scenario which can easily occur, your test kit will give a reading of 0 when your iodine level may already be dangerously high, prompting you to add even more iodine to an already overdosed system.