The HORIBA LAQUA WQ-300 Series is a modular handheld platform: one meter body, interchangeable sensor heads, and replaceable sensor cartridges. Instead of buying a separate instrument per parameter, you buy the channel capacity you need and add or swap sensors as your monitoring program changes.

The series measures pH, ORP, ion concentration, dissolved oxygen, conductivity, resistivity, total dissolved solids, salinity and temperature. Sensor heads connect on 2 m or 5 m cables, and each head takes a screw-in cartridge — so when a pH or ion sensor reaches end of life you replace a low-cost cartridge rather than a whole electrode.

How many channels

• WQ-310 — 1 channel. One sensor connected at a time.
• WQ-320 — 2 channels. Two sensors read simultaneously, for example pH and conductivity together.
• WQ-330 — 3 channels. Three sensors at once, for example pH, conductivity and dissolved oxygen in a single reading.

All three run on AA alkaline or AA Ni-MH rechargeable batteries. The micro-USB port supplies external power but does not charge batteries. Data logging and printer output are built in.

Meter and case, or complete kit

Meter with carrying case supplies the instrument and case with no sensors — the right option if you are adding a meter body to sensors you already own, or specifying your own sensor combination from the accessories range.

Complete kits arrive ready to measure:

• WQ-310 pH kit — 300-PH-2 pH sensor head (2 m cable) and 300-P-C pH cartridge, pH 4.01 / 7.00 / 10.01 standards (60 mL), carrying case
• WQ-310 EC kit — 300-C-2 conductivity sensor head (2 m cable) and 300-4C-C four-cell cartridge, conductivity standards at 84 µS/cm, 1413 µS/cm, 12.88 mS/cm and 111.8 mS/cm (60 mL), carrying case
• WQ-310 DO kit — optical dissolved oxygen sensor head (2 m cable), carrying case
• WQ-320 pH/EC kit — both pH and conductivity heads and cartridges with all standards above, carrying case
• WQ-320 pH/DO kit — pH head and cartridge with pH standards, plus optical DO head, carrying case
• WQ-330 pH/EC/DO kit — pH, conductivity and optical DO heads with cartridges and all standards, carrying case. The complete three-parameter package.

Why optical dissolved oxygen

The WQ-300 DO sensor is optical rather than membrane-galvanic. There is no membrane to puncture, no electrolyte to top up, and no stirring dependency — measurement is stable and the only consumable is the replaceable sensor tip. It costs more up front than a galvanic electrode and repays it in maintenance time.

Applications

• Environmental monitoring of surface water, groundwater and effluent
• Drinking water and wastewater treatment plant process control
• Ion monitoring for ammonium, nitrate, potassium, calcium and sodium using ISE cartridges
• Aquaculture and hatchery dissolved oxygen management
• Industrial process, boiler and cooling water control
• Ultrapure and deionized water verification using resistivity
• Research and teaching laboratories needing one platform across many parameters

Documentation

• LAQUA WQ-300 Series brochure and specifications (PDF)
• LAQUA WQ-300 Series instruction manual (PDF)
• WQ-300 pH meter quick guide (PDF)
• WQ-300 conductivity meter quick guide (PDF)

Parts & accessories

Sensor heads in 2 m and 5 m cable lengths, pH, conductivity, ORP and ion cartridges (ammonium, nitrate, potassium, calcium, sodium), replacement optical DO sensor tips, BNC adapters and calibration solutions are all stocked — see the Horiba Parts & Accessories collection.

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