Precision Labs Potassium Iodide Starch Test Strips, Pack of 1,200

These test strips detect free iodine, chlorine, and peroxides in solution. Lower levels react with the strips at 5 to 10 ppm. Iodine requires approximately 60 sec to react. Package of 12 vials; 100 strips per vial. Instructions for use: Remove 1 test strip from a vial, being careful not to touch the paper anywhere other than where you grasp it. Dip the strip into the solution to be tested for 1 to 2 sec. Remove the strip and shake off any excess liquid. Chlorine and peroxides react immediately, but iodine requires about 1 min to react. Initial reactions show a slight blue color; higher concentrations turn the strip from dark blue to purple. The upper limits for chlorine and peroxides fall between 400 to 450 ppm, and the upper limits for iodine range from 50 to 100 ppm.