Turbidity Tube (Water Clarity Tube) – 10–400 NTU Scale

Measure and compare the clarity of stream, river and other water samples with this two-section turbidity tube. Designed for school environmental science, freshwater fieldwork and water-quality investigations, it provides a practical visual estimate of turbidity using a graduated NTU scale.

The transparent tube is assembled for use and separates into two sections for easier storage and transport. It is particularly useful for hands-on investigations where an electronic turbidity meter is not required.

How does a turbidity tube work?

A turbidity tube provides a simple visual method of estimating water clarity. A water sample is viewed down the clear tube towards a contrasting marker at its base. The visibility of this marker is used to estimate turbidity against the printed NTU (Nephelometric Turbidity Unit) scale.

The 10–400 NTU scale is non-linear, so the spacing between graduation marks is not uniform. This makes the tube useful for comparing water samples during stream studies, environmental monitoring and classroom investigations. It may also be used for general wastewater clarity observations, but is not suitable for verifying low-turbidity disinfection targets below its measuring range.

Key features

• Graduated 10–400 NTU non-linear scale for approximate visual readings
• Two-section design for convenient transport and storage
• Clear polycarbonate construction
• Suitable for classroom experiments, stream studies and environmental monitoring

Specifications

• Material: Clear polycarbonate
• Tube diameter: 2.5 cm
• Assembled length: 60.5 cm
• Scale: 10–400 NTU (visual/approximate)
• Supplied with: Instruction sheet

Note: Results are approximate visual estimates intended for comparative field investigations, not laboratory-grade measurements from a calibrated electronic turbidity meter.