Procedure>
(1) Pull the string of the PACKTEST tube to open a hole.
(2) Hold the tube with the hole up and push the air in the tube out.
(3) Immerse the hole in the tube in a water sample, and siphon off the water sample to about half of the tube.
(4) Shake the water sample in the tube for 10 s and stand for 2 min.
(5) Determine the concentration by comparing the color of the water sample in tube to the colorimetric analysis chart provided with the kit.