The Apera TN400 (AI481) is a portable turbidity meter designed to measure suspended particles in water and aqueous solutions. It uses an 860 nm infrared LED and a 90° nephelometric measurement method compliant with ISO 7027 and DIN EN 27027. Its 0–1,000 NTU range, two measurement modes, and waterproof housing make it suitable for checking source water, filtration performance, nutrient reservoirs, and irrigation runoff.
• Brand: Apera Instruments
• Model / SKU: TN400 / AI481
• Measurement Range: 0–1,000 NTU with automatic range switching
• Measurement Method: 90° nephelometric scattering
• Compliance: ISO 7027 and DIN EN 27027
• Light Source: Infrared LED, 860 ± 30 nm
• Accuracy: ≤ ±2% of reading plus stray light
• Repeatability: ≤ ±1% or 0.02 NTU, whichever is greater
• Measurement Modes: Normal single reading or Average mode using 10 consecutive readings
• Protection Rating: IP67, dustproof and suitable for temporary immersion
• Power Supply: 4 × AA batteries, included
• Included Accessories: Five AMCO Clear® calibration standards (0, 20, 100, 400, and 800 NTU), sample vials, and supporting accessories
Key Advantage: The TN400 combines ISO-compliant infrared measurement with a rugged, portable design and 10-reading averaging mode. Its color-resistant measurement method helps reduce interference from colored samples, supporting more consistent turbidity checks for water treatment and commercial irrigation systems.