Online pH, conductivity, dissolved oxygen, and turbidity analyzers for coolant chemistry monitoring and corrosion prevention in liquid-cooled data centers.
Coolant chemistry drift is the slow, silent failure mode of liquid cooling infrastructure. pH drifting outside the 8.0–9.5 inhibited range, conductivity climbing from ion accumulation, or dissolved oxygen rising from a leaking seal all foreshadow corrosion of cold plate channels, pitting of stainless piping, and premature failure of elastomer seals — long before any thermal alarm fires.
Supmea's online analyzer range covers the four coolant parameters most closely correlated with equipment health. Continuous measurement, auto-cleaning probes, and BMS integration turn coolant chemistry from a quarterly lab-sampling activity into a real-time telemetry stream.
| Measurement range (pH) | 0.00 – 14.00 pH |
|---|---|
| Measurement range (ORP) | −2000 to +2000 mV |
| Resolution | 0.01 pH / 1 mV |
| Accuracy | ±0.02 pH / ±2 mV |
| Temperature compensation | Automatic (Pt1000 integrated); 0–100 °C |
| Calibration | 1-, 2-, or 3-point auto-recognition (buffer 4.00, 6.86, 9.18, 10.01) |
| Electrode lifespan | 12–24 months typical in glycol-water service |
| Output | Dual 4–20 mA, RS-485 Modbus RTU, 3× relay contacts |
| Display | 4.3″ color LCD with trend graphing |
| Enclosure | IP65 wall-mount; panel-mount variant available |
| Sensor mounting | Flow-through, submersion, insertion (ball-valve retractable) |
| Approvals | CE, RoHS |
| Conductivity range | 0 – 200,000 µS/cm (6 auto-ranging scales) |
|---|---|
| Conductivity accuracy | ±1.0% of reading |
| Resistivity range | 0 – 18.25 MΩ·cm (for purified water loops) |
| TDS range | 0 – 100,000 mg/L (configurable factor) |
| DO measurement principle | Optical luminescence (fluorescence quenching) |
| DO range | 0 – 20 mg/L (0 – 200% saturation) |
| DO accuracy | ±0.1 mg/L (< 10 mg/L); ±0.2 mg/L (> 10 mg/L) |
| DO drift | < 0.05 mg/L per month (optical sensor) |
| Turbidity range (SUP-TU720) | 0 – 1000 NTU, accuracy ±5% |
Typical deployment points in data center liquid cooling architectures — from facility water through to rack-level manifolds.
Continuous pH measurement in primary and secondary loops detects buffer depletion and inhibitor breakdown before corrosion begins. Trending pH over time reveals when to refresh corrosion inhibitor packages.
Step changes in coolant conductivity signal ingress of facility water (high conductivity) into a glycol loop, or dielectric fluid contamination in immersion systems (low conductivity baseline shifting).
Optical DO sensors track the effectiveness of oxygen scavenger dosing and reveal air ingress at pump seals, expansion tank membranes, or makeup water. Keeping DO below 100 ppb is critical for copper and brass cold plate channel longevity.
High-range resistivity monitoring (up to 18.25 MΩ·cm) for deionized water makeup loops used in high-purity cooling applications, verifying ion exchange resin performance.
Turbidity trending reveals biofilm detachment events, particulate shedding from pipe corrosion, or filter bypass conditions — a leading indicator of heat exchanger fouling.
Analyzers on makeup water feed lines verify incoming water quality meets specification before entering the coolant loop, preventing contaminated makeup from compromising the whole system.
Send us a P&ID or a short description of your cooling loop. Our application engineers respond with a specification recommendation and quote within one business day.
The questions we hear most often from specifying engineers, system integrators, and facility operators.
pH and conductivity are the two parameters worth continuous online monitoring — they drift on timescales (weeks to months) where early detection matters, and the sensors are durable and low-maintenance. Dissolved oxygen is worth continuous monitoring in loops with copper or brass components. Turbidity is typically a diagnostic measurement rather than a routine one. Inhibitor concentration, hardness, chloride, and sulfate are better handled by quarterly grab-sample lab analysis — online analyzers for these parameters exist but are specialized and expensive.
For inhibited propylene glycol coolants, the typical target range is 8.5–10.0, buffered by the inhibitor package. pH below 7.5 indicates inhibitor depletion and imminent corrosion risk. pH above 10.5 can indicate ammonia contamination or over-dosing. Your coolant supplier will provide a specific target range and re-inhibition threshold for their formulation — our analyzers log time-at-threshold to support scheduled maintenance decisions.
Glass pH electrodes in glycol-water service typically last 12–24 months before slope degradation exceeds calibration-compensable limits. Agitated high-temperature service is harder on electrodes; clean, low-flow installations extend life. The SUP-PH700 reports electrode impedance continuously, which is the leading indicator of end-of-life — we recommend replacement when impedance exceeds 500 MΩ or slope drops below 90%.
Yes, substantially. Optical (luminescence-quench) DO sensors have no electrolyte to consume and no membrane to permeate, so drift is typically under 0.05 mg/L per month versus 0.2–0.5 mg/L per month for Clark-cell electrochemical sensors. For low-DO applications (< 100 ppb) in closed cooling loops, optical is the only practical choice. Calibration intervals are correspondingly longer — 3 to 6 months for optical, monthly for Clark-cell.
Indirectly. Dielectric immersion fluids have conductivity below 0.1 µS/cm under normal conditions — below the measurement floor of general-purpose conductivity sensors. To detect water-based contamination of dielectric fluid, specify a high-resolution low-range conductivity cell (0–20 µS/cm range with 0.01 µS/cm resolution). For detecting dielectric fluid leaking into a water loop, standard conductivity works — the dielectric fluid signature is an abrupt drop in water conductivity.
All analyzers support 4–20 mA analog output (dual, allowing pH and temperature on separate channels), RS-485 Modbus RTU, and 3× programmable relay contacts for threshold alarming. Modbus TCP over Ethernet is available via a built-in converter option. For DCIM systems requiring SNMP, we recommend an external Modbus-to-SNMP gateway.
Clean, inhibited glycol-water loops are a benign service environment — pH electrodes and conductivity cells typically do not require cleaning between electrode replacements. For loops with biofouling risk (open cooling towers, outdoor makeup tanks), we offer auto-cleaning probe holders with scheduled brush or air-purge cycles. These are rarely needed for enclosed data center primary or secondary loops.
Whether you're designing a new liquid-cooled data center or retrofitting existing air-cooled facilities, our engineers can help you select the right instrumentation package.