The HORIBA U-51 is a rugged, field-portable multiparameter water quality meter that measures eight parameters simultaneously from a single submersible probe — one deployment gives you a complete water quality snapshot instead of juggling several separate meters.

A handheld control unit pairs with a stainless-steel-guarded sensor probe on a direct-read cable. Every parameter appears on screen at once, logs to internal memory, and downloads to a PC using the U-50PC software. Control unit and probe are both built for wet, dirty work in monitoring wells, streams and treatment plants.

Measured parameters

• pH
• ORP (redox potential)
• Dissolved oxygen (DO)
• Electrical conductivity
• Salinity
• Total dissolved solids (TDS)
• Seawater specific gravity
• Temperature

Cable lengths

• 2 m cable (part no. 3200164509) — surface water, flow cells, beaker and bucket readings
• 10 m cable (part no. 3200164510) — typical shallow monitoring wells

Choose the length to match your deepest measuring point.

Applications

• Groundwater monitoring well sampling and low-flow purge stabilization
• Surface water surveys of rivers, lakes, streams and reservoirs
• Coastal, estuarine and brackish water monitoring using the seawater and salinity channels
• Municipal and industrial wastewater and effluent discharge checks
• Drinking water source and distribution spot checks
• Aquaculture, irrigation and agricultural runoff monitoring
• Environmental compliance sampling and site characterization

Documentation

• U-50 Series specifications (PDF)
• U-50 Series instruction manual (PDF)
• U-50PC software instruction manual (PDF)
• U-50FC flow cell instruction manual (PDF)

Parts & accessories

Replacement pH, ORP and DO sensors, reference electrode tips, DO membrane caps, probe guards, O-ring sets, carrying cases, flow cells, calibration beakers and standard solutions are all stocked — see the Horiba Parts & Accessories collection.

Browse all HORIBA instruments.