The Purezone will measure FC and display that measurement with values between 0.0ppm and 25.4ppm.  The Purezone clips the high value for FC at 25.4ppm. 

If your Purezone is reading FC of 25.4ppm consistently, your actual FC reading is probably much higher. An FC reading of 25.4 or higher is telling you that the water is not safe.

• Pool Store DPD Tests and Test Strips are NOT able to accurately read measurements of high FC because the pads bleach out: 
  • https://web.archive.org/web/20230803041438/http://www.taylortechnologies.com/en/content/technical-supportfaqs
  • https://taylortechnologies.com/pages/technical-faqs
• Unlike Pool Store DPD Tests (that measure FC) and Pool Store and Home Test Strips, the Purezone FC test pads do NOT bleach out and will display accurate measurements for high FC conditions
• Note: In some cases high FC levels in a water body can also make the pH levels read artificially high

Please take steps as soon as possible to address the high FC condition.