300ppm Cl Color Chart

SKU: 33815-300

$9.95USD or lower Each

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[4.7]   3 Reviews    | Write a Review

These Indigo® 300ppm free (available) chlorine test strips are easy to use & an essential tool for anyone in the food processing business. Get accurate results in just 5-10 seconds.

Confused about how to dilute? Use our free Chlorine bleach dilution calculator to take out the guesswork.


Use our bleach dilution calculator to take out the guesswork out of trying to calculate how to prepare a 50, 100, 200 (or other) ppm chlorine solutions. 

Related information or images
Results in 5-10 seconds with readings at 25, 50, 100, 200, 300 ppm for free (available: HOCl & OCl-) chlorine bleach concentration. This strip has a detection limit of 2-3 ppm.
  • Indigo™ test strips have a guaranteed minimum 3 year shelf life but are stored in desiccant lined vials so actual shelf life can be 5+ years.
  • For technical explanation, read: Sanitizer Test Strip Expiration; Good Today, Dead Tomorrow?
  • These strips measure free (available) chlorine
  • The number of strips (100) per vial is approximate.

Test Strip Documentation

Stability Statement Certificate of Analysis SDS Calibration Fluid CoA
Indigo Chlorine 300ppm Test Strip Stability Statement
Indigo Chlorine 300ppm Test Strip Certificate of Analysis
Indigo Chlorine 300ppm Test Strip SDS Calibration Fluid Certificate of Analysis

Indigo® brand chlorine test strips are Made in USA & tested for accuracy using NIST compliant standards.

Reviews (3)

The high chlorine test strips are handy for operators to measure Free Chlorine levels to ensure adequate dosages have been achieved when disinfecting watermains and cleaning storage facilities. They arrived very quickly.

— LindaT
— Indigo:

Interesting applications, thanks for the feedback.


I am glad these are packaged in a container; we have had some in the past packaged in a paper envelope (from another company), which is hard to keep dry. They work just as advertised - the only imperfection for us is that the colors are fairly similar and it can be hard to tell at a glance what the result is. Otherwise, great.

— Lettuce
— Indigo:

Thanks for the feedback. The packaging for most sanitizer test strips come in special desiccant lined containers which is explained further in: Test Strip Expiration Dates; Good Today, Dead Tomorrow?

Some of the color charts are indeed harder to read than others. Good lighting can help. Fluorescent lighting is not as contrast friendly as natural sunlight or halogen or quartz.

These Chlorine test strips are great when you need to measure Free Chlorine levels in water at high levels of concentration.
— Great product, arrived quickly.
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