Hydrion 0-1000 chlorine test strips measure the concentration of free chlorine in sanitizing/disinfecting solutions. The color chart has matches at 0-50-100-250-500-800-1000 ppm. Carton includes 6 vials of 100 strips.
Dip strip into solution for 1 second. Remove strip and shake off excess solution. Match to color chart within 5 seconds for accurate free chlorine measurement.