What Your Test Strip Isn't Telling You About Chlorine Dioxide

You mix your chlorine dioxide solution, run a test strip, see a positive reading, and assume you're good to go. But here's what we've learned through our research: that strip may not be telling you the whole story.

Our research team recently evaluated four ready-to-use chlorine dioxide solutions and tested them against five different test strips and one titration kit, comparing everything to a laboratory reference method. Here's what stood out: only one of the five test strips stayed consistently accurate. The others either underreported or overreported concentrations. Some even produced positive readings in solutions that couldn't have generated any active chlorine dioxide at all.

At DeLaval, we know that dairy producers rely on disinfectants like chlorine dioxide to protect herd health and milk quality. It's a powerful tool, but only when it's actually working. We also know that on-farm testing isn't always straightforward. Many producers use test strips or titration kits to verify their solutions, but these tools have real limitations that can mask problems.

Test strips measure "total chlorites," which includes both active chlorine dioxide and inactive precursor ingredients. That's the problem. A high reading might just mean your solution contains the ingredients, not that it's generating enough active chlorine dioxide to be effective, or that it's not exceeding safe levels.

When a test can't tell the difference between active and inactive components, you're getting incomplete information. And incomplete information puts your herd’s udder health and milk quality at risk. If your dip isn't effective, mastitis risk rises. If there's too much active chlorine dioxide, you have a safety concern. Either way, you're making management decisions on a false positive.

If you're going to test your chlorine dioxide on farm, don't rely on a single tool. A two-part approach gives you better information: use one test to confirm your sodium chlorite base was properly dosed and mixed, then use another to verify that active chlorine dioxide was actually generated.

The most reliable path is following your product label instructions exactly. The label dosing, mixing ratios, and timing have been engineered to deliver a safe, effective solution. 

Read the Full Research

We've published a white paper on this topic with detailed findings and practical guidance. Download it to see the test results, understand which tools work best together, and learn how to verify your solutions with confidence.

Download the White Paper

"What Test Strips Don't Tell You: Getting Chlorine Dioxide Right On Farm"

Questions about your specific operation? Contact your local DeLaval dealer.