Chlorine Test Strips

Need Affordability & Reliability

100 Strips/Bottle

3 Year Shelf Life

Indigo® chlorine test strips for water, food handling, daycare, healthcare & medical device sanitizing and disinfection needs.

  • 6 different ranges
  • All test strips100/pack
  • 3 year minimum shelf life (while unopened)
  • Discounts for 2, 3 & 10+ for unbeatable savings
  • Certificates of Analysis, Stability & SDS Statement
  • Certificates of Conformance on request
  • Optional next day delivery in any quantity of most items

Buy Indigo® test strips, the brand you can trust for accuracy & technical support. Call us on our toll free line for immediate assistance or e-mail us with your questions. 1 hour response is typical during business hours, M-F, slightly longer on weekends.

Customer Reviews on Google

"The quick and prompt service on my 0-10 ppm chlorine test strips is much appreciated...quality at a cost less than Amazon. Read the full review from Helen K

Indigo Instruments defines the purpose for the test strips and places them in easy to recognize categories... BONUS is the qty of strips in each vial (100 vs the typical 50), fast and consistently accurate all for a price that beats other sellers! Read the full review from Roberta V.


Chlorine (Hypochlorite) Sanitizer-Disinfectant

Hypochlorites are the most commonly used of the chlorine based disinfectants, are fast acting & economical. Sodium hypochlorite (chlorine bleach) is strongly oxidizing with a broad range antimicrobial action that can disrupt or destroy bacterial cell membranes. This happens because because cell walls of pathogenic microorganisms are negatively charged. Hypochlorite germicidal activity is directed towards important bacterial enyzmes which in turn disrupts metabolic pathways. Effectiveness of hypochlorite (chlorine bleach) solutions are reduced in the presence of organic compounds such as blood and feces. Higher concentrations are often required to break down biofilms.

Hypochlorite ion (OCl-, shown in the image below) reacts with water to form hypochlorous acid (HOCl) that is the actual disinfecting compound. The amount of hypochlorous acid and hypochlorite together equals available or free chlorine. Its broad range of antimicrobial action is unaffected by water hardness. In high enough concentration, it can effect a 5-log reduction (99.999% inactivation) in pathogenic organisms in under 10 minutes. 

Hypochlorite disinfectant chemical structure

Hypochlorite disinfectant structure model from Indigo® Instruments. Sodium or calcium ion not shown.
Follow precision chlorine test paper instructions for guaranteed accuracy with Indigo® Chlorine Test Strips

Indigo® chlorine test strips measure concentrations ranging from 0.5ppm to 10,000ppm high levels for applications ranging from water treatment, food service, biofilms to medical devices & more. Whatever your strength requirement for chlorine bleach/hypochlorite, Indigo® chlorine test strips can confirm your disinfectant solutions are correctly diluted for optimum effectiveness. Get the best chlorine test strips for your application.

  • 0-10ppm (available): 0-0.5-1-3-5-10ppm; read results in 30 seconds
  • 0-200ppm (total): 10-50-100-200ppm; read results in 1 second
  • 0-300ppm (available): 0-25-50-100-200-300ppm; read results in 5-10 seconds
  • 0-1000ppm (available): 0-50-100-250-500-1000ppm; read results immediately
  • 0-2000ppm (available): 0-25-50-200-500-800-1500-2000ppm; read results in 60 seconds
  • 0-10000ppm (available: 0-1000-2500-5000-7500-10000ppm; read results in 10 seconds
Displaying 1 to 7 (of 7 products)
Chlorine Test Strips, 0-200ppm Food Preparation

Chlorine Test Strips, 0-200ppm Food Preparation

SKU: 33815-200
$2.55USD or lower Each
300ppm Chlorine-Food Safety

300ppm Chlorine-Food Safety

SKU: 33815-300
$8.95USD or lower Each
Chlorine Disinfection Test Strips 1000ppm

Chlorine Disinfection Test Strips 1000ppm

SKU: 33815-1000
$14.95USD or lower Each
High Range Sodium Hypochlorite Test Strips

High Range Sodium Hypochlorite Test Strips

SKU: 33815-10K
$26.95USD or lower Each
Bleach Disinfection Test Strips 2000ppm

Bleach Disinfection Test Strips 2000ppm

SKU: 33815-2000
$15.95USD or lower Each
Residual Chlorine Test Strips 0-10ppm

Residual Chlorine Test Strips 0-10ppm

SKU: 33815-10
$21.95USD or lower Each
50ppm Iodine Test Papers

50ppm Iodine Test Papers

SKU: 33815-I
$2.95USD or lower Each
More Information

Common Features of Plastic Chlorine Test Strips

  • Clear instructions with labelled color chart
  • White plastic strips for high contrast accurate reading
  • Stiff plastic strips ideal for dipping
  • Paper-based chlorine & iodine strips for low range/economy testing
  • 3-year guaranteed shelf-life
  • Certificate of Analysis, Stability Statement & SDS on-line.
  • Certificate of Conformance on request

Note: All test strips Made in the USA & are Q/A'd against NIST standards.

Sodium Hypochlorite, Iodine Pros & Cons

Chlorine (sodium hypochlorite) is the most popular sanitizing/disinfecting chemical for hard surfaces especially where food is prepared. Iodine, also a halogen, is listed below but is used relatively rarely by comparison.



  • Can be corrosive
  • Not affected by hard water
  • Generally inexpensive


  • Corrosive to eyes, skin, respiratory tract
  • Can be irritating to the skin
  • Deteriorates over time
  • Loses some activity in the presence of organic matter



  • Not affected by hard water
  • Less irritating to the skin than chlorine
  • Activity is not lost rapidly in the presence of organic matter


  • Effectiveness decreases greatly with increase in pH
  • Should not be used in water > 50°C
  • May also discolor equipment and surfaces

Additional material that may interest you:

  1. Test Strip Expiration Dates; Good Today, Dead Tomorrow? Don't toss good test strips away. Good today doesn't mean bad tomorrow.
  2. Diluting Chlorine, Peroxide, Quats is Easy. Dilute any concentration of disinfectant to any ppm for bottles or bucketfulls.
  3. What Kills Norovirus on Surfaces? Chlorine bleach works fine on any hard surface from dishes to doorknobs.
  4. Wash, Rinse, Sanitize: The Three Sink Method. A simple technique for kitchens anywhere.
  5. Chlorine Bleach Disinfectant-An Old Chemical for New Bugs. Frequent cleaning doesn't have to be expensive.
  6. Chlorine Test Strips-Daycare Disinfection Checklist. Common & not so obvious things to disinfect not only in daycare but office, business or home.



How to Dilute Chlorine & Iodine

The color charts on chlorine (hypochlorite) and iodine test strip bottles indicate concentrations from 10 ppm up to 10000ppm. Use our chlorine bleach ppm dilution calculator to take the guesswork out of making up accurate sanitizer solutions.

Simply Enter:
  1. Strength of your chlorine bleach (%)
  2. Strength you want after dilution (ppm)
  3. How much you need to prepare (litres, mL)
  4. Press "Calculate"
It will tell you how much undiluted chlorine bleach to mix with water. Confirm solutions are in the correct range with the appropriate Indigo® test strip. Dilution calculator lists equivalents for conversion to American units of measure.

Warning. Chlorine use in sanitation and disinfection has rare cases of serious toxicity but careful handling is nevertheless recommended. Fumes from undiluted household bleach can cause eye irritation. Ingestion can cause oropharyngeal, esophageal & gastric burns. Nitrile gloves, safety glasses and lab coat/apron are the minimum recommended PPE (personal protective equipment) for handling concentrated chlorine bleach.

Never mix chlorine bleach-sodium hypochlorite with ammonia based cleaners which can release toxic levels of ammonia and chlorine gas

Consult first aid instructions on bleach container & seek medical aid if necessary in the event a spill or mishap.

How to Use Chlorine Test Strips?

Instructions for chlorine/chlorine dioxide/iodine test strip use is the same regardless of concentration range.
  1. Remove test strip from vial.
  2. If paper, dip any end in bleach solution
  3. If plastic, dip pad end in bleach solution
  4. Remove and compare to color chart. Times vary-see individual strips for specifics.
Frequently Asked Questions

FAQ for Chlorine & Iodine

The biochemical mechanisms for chlorine's microbiocidal properties are not well understood. They range from breaking disulfide bridges that occur between cysteines (an amino acid) in enzymes, decreased production of ATP (the energy transfer molecule in cells), to breaks in the bonds in the DNA double helix strands.

Paper chlorine test strips never expire; the expiration date is only for stock rotation purposes. Indigo® plastic backed chlorine test strips have a guaranteed 3 year shelf life. If unopened, they can last nearly 10 years. With proper storage, chlorine test strips are good long after the stated expiration date. For more information see our blog: Test Strip Expiration Dates; Good Today, Dead Tomorrow?

Test strips are typically accurate to within +/- 10% which is typical of a semi-quantitative detection method. Fully quantitative techniques like titration can be many times better.

All Indigo® plastic chlorine test strips measure available (free) hypochlorite ions + hypochlorous acid. Paper based chlorine bleach test strips measure free & bound chlorine.

Any of our test strips can be used at home. Check with local health authorities for the optimum concentration  needed for your task. Typically, the 200ppm chlorine test papers will be enough for routine dish & eating utensal washing. You can use our free on-line chlorine dilution calculator to mix concentrated bleach with water for the range you need.

It is very cheap; you can use off the shelf chlorine bleach (Chlorox) for a wide range of applications. Even when heavily diluted, it will still kill bacteria and not be toxic to humans.

Municipal drinking water should only have residual levels of chlorine, less than 4 ppm (4 mg/L). If you are still concerned, fill a jug & keep it in the fridge for 24 hours with the pour spout open to air. Dissolved chlorine comes of out solution readily.

1 ppm of chlorine in drinking or pool water should kill these amoebae in 10 minutes.

The 0-10ppm residual strips should be sufficient for tap water which is supposed to be limited to 4 ppm (4 mg/L) or less.