Our favorite all-around test kits are the red sea kits.  With easy to follow directions, and consistent results, we always have a Red Sea Iodine Pro test kit in our testing closet.  With most other Iodine tests comparing the results can be difficult especially if you have bad eyes, however, Red Sea is probably one of the easiest to differentiate the color.

Iodine Pro Kit includes 50 tests. Easy to use colorimetric comparator. High quality and reliability. Affordable reagent refills.

Kit Includes: 50 tests
Test Type: Colorimetric comparator
Accuracy: ±0.01 ppm
Range: 0-0.09 ppm
Affordable reagent refills