Why doesn’t my TDS meter show a difference after using Weddell Duo?Updated 9 days ago

Handheld TDS (Total Dissolved Solids) meters are designed for drinking water and primarily measure dissolved minerals such as calcium and magnesium. These minerals are safe and not the focus of our shower filtration system. That’s why your TDS reading may look the same before and after using the Duo — the meter is only detecting the natural minerals that remain in the water.

The Weddell Duo is NSF certified and independently verified to reduce contaminants that TDS meters cannot measure, including:

• Free available chlorine (NSF/ANSI 177 certified)
• PFAS (“forever chemicals”) and particulates (verified to NSF/ANSI 53 and 42 standards for shower filters)

These are the contaminants that affect skin, hair, and scalp health — not total mineral content. Unlike drinking water filters (such as under-sink systems), shower filters are not designed to reduce TDS.

You can review our independent lab test results here.