Features Catalysis based, sensitive to less than 0.0025 mg/L Multi-cavity plate for simultaneous testing of up to 6 tests at the same time Includes reference for test validation Marine or Freshwater Natural seawater (NSW) concentration of iodide is 0.06 mg/L. Ideally, it is advisable to maintain iodide close to NSW concentration. Concentrations above NSW may not be harmful, and, within limits, may even be bene?cial, but maintenance at elevated concentrations should be considered experimental. The innovative MultiTest™ Iodine/Iodide kit offers a quantitative test for this important element of soft and hard coral growth. It measures iodine or iodide to less than 0.005 mg/L. The color scale peaks at 0.10 mg/L. It performs over 75 tests and contains a reference sample for validation. Features 75 Tests - MultiTest™ Iodine & Iodide performs over 75 tests And with the multi-cavity test plate, multiple tests can be run at the same time. Accuracy Range - Measures between 0–0.1 mg/L iodine or iodide Precision - Detectable changes on the color chart in 0.0025–0.005 mg/L increments. Reference Sample - It isn't necessary to run a reference test to use this kit; however, its proper performance can be validated by running a test in the normal manner except that the reference sample is used in place of aquarium sample. You might choose to run a reference test if you have cause to believe the test is giving incorrect results. Color Chart All MultiTest™ test kits come with an easy-to-read color chart. It features a 5 cm viewing window to help isolate color and match as closely as possible to the test sample Opaque Multi-Cavity Test Plate All MultiTest™ test kits are read from an opaque white test plate. The sliding color chart along with the six-cavity test plate allows for easy reading and comparisons of several samples at the same time.