China Dissolved Oxygen Meter For Fish Farming Suppliers & Factory

Polarographic and galvanic DO sensors require a continuous flow of water across a fragile permeable membrane because they chemically consume dissolved oxygen molecules during measurement. In static pond water or low-flow nursery tanks, this consumption creates artificial localized hypoxia at the sensor tip, resulting in falsely low readings. Furthermore, aquaculture biofouling (algae and microbial film) quickly clogs standard membranes, requiring weekly electrolyte top-ups and recalibration. Optical DO sensors measure the phase shift of reflected red light after blue light excites a ruthenium fluorophore; they consume zero oxygen, do not require water movement, and typically run 6 to 12 months with only basic wipe cleaning.

Under Henry’s Law, the solubility of oxygen in water decreases as salinity increases (known as the "salting-out" effect). Seawater at 35 ppt holds roughly 20% less dissolved oxygen at saturation compared to freshwater at the identical temperature. BOQU online transmitters and digital sensors feature integrated salinity compensation algorithms. Users can either input a fixed salinity value (e.g., 30 ppt for a specific shrimp pond) or feed a live 4-20mA/RS485 signal from a BOQU conductivity sensor directly into the transmitter to achieve continuous, dynamic salinity-compensated DO concentration (mg/L or ppm) readouts.

Sensors should typically be installed at a depth between one-half and two-thirds of the total water column, and mounted at a 45-degree downward angle using an immersion bracket to prevent air bubbles from lodging on the optical cap. In earthen ponds, keep the probe at least 50 cm above the sludge bottom to prevent sediment burial, and position it away from direct paddlewheel discharge plumes so you measure bulk water oxygen rather than artificial localized bubbles.

BOQU Instrument is an authentic, vertically integrated manufacturer established in Shanghai in 2007. We operate 4,632 square meters of owned production floorspace split across our Kangqiao and Lingang workshops. We design our own PCB layouts, formulate sensing glass and optical caps in-house, run cleanroom SMT production, and calibrate every batch on multi-station automated test benches. Global clients are welcome to inspect our facilities via on-site audits or interactive 360-degree VR factory tours.

BOQU instruments offer standard industrial telemetry outputs. Analyzers provide isolated 4-20 mA outputs (one for DO, one for Temperature), two configurable SPDT mechanical relays (capable of directly triggering motor contactors or VFD start commands with configurable hysteresis bands), and standard RS485 Modbus RTU. Our IoT smart digital sensors output RS485 Modbus directly from the sensor cable, allowing daisy-chaining directly into environmental PLCs, telemetry RTUs, or IoT cloud gateways.

Under typical aquaculture conditions, the luminescent coating on the BOQU optical DO cap lasts between 18 and 24 months. Cap replacement takes less than two minutes: simply unscrew the old cap, seat the new pre-calibrated optical cap with its O-ring, and enter the calibration factor or perform a standard one-point air saturation verification.

Yes. While aquaculture ponds generally use manual wiping, hatcheries, RAS piping, and pharmaceutical fermentation lines require high-temperature steam sterilization or acid/alkali CIP cycles. BOQU produces dedicated steam-sterilizable sensors—such as the pH5806 (Shanghai Brand certified) and DOG-208FA high-temperature DO sensor—capable of enduring repeated 130°C autoclave and steam sterilization cycles without signal degradation.