Ecoleaf - Hydrion Chlorine Test Paper provides a simple, reliable, and economical means to measure the concentration of free available chlorine in sanitizing solutions. With color matches at 10-50-100-200ppm, the test paper
Bartovation Restaurant Chlorine Sanitizer Plastic Test Strips, 0-200 ppm [Moisture Wicking Vial of 100 Strips] : Amazon.co.uk: Garden