Ozone Test Kit - K7404


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California Regulatory Information

SKU: 003634

Product Overview


K-7404 dissolved ozone vacuvials are an accurate and inexpensive way to measure your dissolved ozone levels. Their range is up to 3.0 ppm, but can detect higher levels if the proper sample-dilution instructions are followed. 30 colorimetric tubes included for instant ozone detection. Replacement vials and activator solution are available for purchase online.


  • Low cost accuracy.
  • Industry-proven chemistry.
  • Useful for standalone ozone sampling -OR-
  • Useful for calibration of ozone process monitors.
  • Wide range.
 More Information
 Weight 1.5000
 Electrical 120 - 240 VAC 60 Hz
 Dimensions 6 x 7.5 x 2.5 inches (15.2 x 19.1 x 6.4 cm)
 Warranty 1 Year
 Display None
 Detection Method DPD
 Temperature Range 32 to 212°F (0.0 to 100°C)
 Accuracy +/- 100%
 Resolution 0.05 ppm (50 ppb)
 Supporting Documents Instructions and comparators included.
 In Stock In Stock
 Min Detect Limit 0.025 ppm (25 ppb)
 Internal Datalogging No
 Display Units ppm
 Comms. Protocol None
 Relays 0


What is the shelf life for this product?

If the shelf life is not stated in the supplied paperwork, it will have a shelf life of two years.

Does the K-7404 react with Chlorine and Bromine?

Yes. The kit reacts with both Chlorine & Bromine. If you use the K-7404 to analyze for bromine, you should multiply ppm ozone result by 3.3 to convert to ppm bromine. If you use the K-7404 to analyze for chlorine, you should multiply ppm ozone result by 1.5 to convert to ppm chlorine.

My A-7400 Activator Solution has a yellowish color, but it is not expired yet. Is this normal?

The acceptable color for this reagent, A-7400, is colorless to pale yellow. The manufacturer has demonstrated many times over the years that this yellow color does not impact the accuracy of the test results.

How do I measure dissolved ozone in chlorinated water?

Chlorine does cause interference on the test results. We advise taking the following steps when measuring ozone in water that has residual chlorine:

1.Establish a baseline reading with chlorinated, ozone-free water.

2.Measure your aqueous ozone.

a.Any levels of ozone below the baseline reading will not register. For example, if your baseline is 1 ppm free chlorine, and your level of ozone is less than or equal to 1 ppm, your readings will consistently show 1 ppm.

b.Once your levels of ozone cross over the baseline, your readings of ozone will be accurate. For example, if your baseline is 1 ppm free chlorine, and your level of ozone is 1.5 ppm, the reading will accurately show the level of ozone at 1.5 ppm.

How do I measure higher levels than 3.0 ppm?

By using dilution, you can measure up to 15 ppm with the K-7404 kit, although the accuracy decreases the more you dilute your sample.

For a 1:1 ratio (zero dilution), add five drops activator solution and put 25 ml dissolved ozone in the sample cup.

For ozone levels around 15 ppm, add five drops activator solution and put 5 ml dissolved ozone in the sample cup. Add clean, ozone-free water to the 25 ml line. Then multiply your readings by 5.

Is the K-7404 510(k) Certified?



Warranty Information

Seller warrants that all Products will conform to the Specifications and will be free from defects in material workmanship and programming. Claims for Products not complying with this warranty shall be submitted by Buyer no later than 12 months from delivery date to Buyer. Seller shall promptly repair or replace, at its option and expense, non-complying Products. The shipment of non-complying Products by Buyer to Seller, and the return shipment of repaired or replacement Products by Seller to Buyer shall be at Seller's expense, unless it shall be determined that Buyer returned a Product that was in compliance, in which case such cost shall be borne by Buyer and, if paid by Seller, these expenses shall be reimbursed by Buyer within thirty (30) days of notice by Seller. Buyer shall receive a credit for any non-complying Products returned for repair or replacement. All non-complying Products shall be returned to Seller (at its offices or as otherwise instructed) no later than 30 days as of the date the non-compliance of any such Product has been discovered. Seller is NOT responsible for any/all damages suffered to the Products that is caused by the Buyer. Such as but not limited to damage by wrong electrical current, damage through crush or dropping the product, damage through untrained users of Product, damage through improper operations.

California Regulatory Warning

Example Image
Use in unoccupied spaces only.
Health hazard warning: emits ozone.

This product is not CARB Certified (Ozone Emissions for Air Cleaners).
Product Disclaimer: Does not meet California air cleaner regulation requirements; cannot be shipped to California.

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