January 23, 2026

Bulletin: Turbidity Expert – 1 NTU Standard Tolerance Update

Dear Valued Customer,

As part of our ongoing commitment to maintaining high performance and reliability in Turbidity Expert, we are implementing a small update to the tolerance applied to the 1 NTU SDVB turbidity standard.

Why this change is being made?

Low‑level SDVB turbidity standards are naturally sensitive to very small impurities within their glassware containers. Over time, these impurities can cause the measured value of the standard to drift slightly upward. This behaviour is well‑known for liquid turbidity standards at very low NTU values.

To ensure your Turbidity Expert continues to perform within expected specifications even as these natural shifts occur, we are making a small adjustment to widen the tolerance range associated with the 1 NTU standard. This does not affect the nominal value of the standard, only the acceptable tolerance band.

What is changing?

Below is an overview of the adjustment:

This update accounts for natural upward drift while maintaining instrument accuracy, repeatability, and compliance with routine turbidity QA/QC practices.

What this means for you

Any standard sets manufactured in January 2026 or after will be set for the updated tolerance. To see this on your instrument, first ensure the firmware is updated to the latest version. Select ‘Check Standards’ from the instrument menu and input the assignment code, as shown on the bottom of the check standard certificate, to assign target values and acceptable tolerances.