Fluorescence dissolved oxygen sensors for Australian water, wastewater, and aquaculture
Optical fluorescence DO sensors — the modern alternative to galvanic and polarographic membrane probes. No electrolyte refills, no membrane replacement, no zero-air calibration. Industrial 316 stainless body for harsh duty, plus a compact 28mm replaceable-cap variant for OEM and aquaculture deployment.
2 SKUs in stock Optical fluorescence 3 week delivery
IDO-F28iIndustrial Fluorescence DO SensorTitanium / 316 SS · RS485 ModbusView ›IDO-F28cCompact Fluorescence DO Sensor28 mm · replaceable capView ›
Why optical fluorescence beats membrane DO probes
Galvanic and polarographic DO membrane probes — the dominant technology for the past 40 years — have well-documented limitations: monthly membrane replacement, electrolyte refills, drift between cleanings, and the requirement for zero-air calibration. Optical fluorescence DO eliminates all four. The sensing element is a luminescent dye coated onto a sensor cap, excited by an LED. Oxygen quenches the fluorescence; the sensor measures the quench rate to derive DO concentration. No moving parts, no consumables beyond the cap (which lasts 12–24 months), and no zero-air step in calibration.
Industrial vs compact — which to specify
The IDO-F28i is the industrial duty sensor: titanium and 316 stainless body for corrosive process duty, RS485 Modbus output, suitable for inline mounting in process pipework with standard threaded or flanged process connections. Specify it for industrial wastewater treatment, mining process water, food and beverage process duty.
The IDO-F28c is the compact variant: 28 mm diameter body with a user-replaceable sensing cap, designed for cost-sensitive OEM integration, aquaculture (RAS) tank monitoring, and small wastewater plant deployments. The replaceable-cap design lets the user refresh the sensing element without replacing the entire sensor head.
HACH LDO and E+H Oxymax alternative
The IDO-F28i and IDO-F28c output RS485 Modbus directly — open-protocol integration into any PLC or SCADA platform without the proprietary controller dependency that comes with HACH LDO probes (which require HACH SC controllers) or Endress+Hauser Oxymax probes (which require E+H Liquiline transmitters). This is the parallel-import value proposition: same fluorescence sensing technology, same measurement performance, no vendor lock-in.
Calibration and maintenance
Optical DO sensors require calibration only once per cap replacement (every 12–24 months) — single-point air-saturation calibration, no zero-air step. Recommended cleaning cycle is monthly for general process duty, weekly for wastewater and aquaculture applications.
Who specifies InstroDirect DO sensors?
Wastewater treatment plants
IDO-F28i on activated-sludge aeration basins, blower control loops, and RAS line monitoring. Modbus RTU into existing CompactLogix or S7-1200 PLCs.
Aquaculture and RAS systems
IDO-F28c (compact, replaceable-cap) on tank-mounted continuous monitoring, biofilter outlet monitoring, hatchery and grow-out facilities.
Food & beverage and brewing
IDO-F28i on fermenter monitoring, dissolved oxygen control loops, and process water quality verification.
Mining and industrial process water
IDO-F28i titanium variant on aggressive process water duty, leach circuit dissolved-oxygen monitoring.
Request a quote
Send us the application, measurement range, mounting, and PLC platform. Contact our technical team or call 0403 082 383.
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