Product Description
Milwaukee CD97 Low Range TDS Pen – Digital PPM Tester with ATC
Monitor water purity with confidence using the Milwaukee CD97 — a compact, digital Total Dissolved Solids (TDS) pen tester engineered for water conditioning, reverse osmosis (RO) system verification, hydroponics, aquarium maintenance, drinking water testing, and science education. Simple, accurate, and built to last, the CD97 delivers reliable ppm readings with Automatic Temperature Compensation (ATC) in a pocket-sized form factor.
Key Features
Low Range TDS Measurement (0–999 ppm) — Ideal for water conditioning, RO filter verification, and drinking water quality monitoring
Automatic Temperature Compensation (ATC) — Corrects readings automatically from 5–50°C (41–122°F) for accurate results regardless of sample temperature
Factory Calibrated — Ready to use out of the box; manual 1-point recalibration available via trimmer when needed
±10 ppm Accuracy — Precise enough for water conditioning targets, filter change decisions, and educational demonstrations
300-Hour Battery Life — 4 × 1.5V alkaline batteries included; long runtime minimizes downtime
ppm to µS/cm Convertible — Readings easily converted to EC using 0.5 (500 scale), 0.7 (700 scale), or 442 scale factors
Compact Pen Form Factor — Lightweight (3.5 oz) and pocket-sized for field, lab, or classroom use
Technical Specifications
TDS Range: 0 – 999 ppm
Resolution: 1 ppm
Accuracy: ±10 ppm
Temperature Compensation: Automatic (ATC), 5–50°C (41–122°F), β = 2%/°C
Calibration: Factory calibrated; manual 1-point via trimmer
Calibration Solution: M10080B — 800 ppm TDS sachets (25 × 20 mL)
Battery: 4 × 1.5V alkaline (included) | Battery Life: ~300 hours continuous
Operating Environment: 0–50°C (32–122°F); max RH 100%
Dimensions: 6.0 × 1.2 × 0.95 in (180 × 65 × 32 mm)
Weight: 3.5 oz (99 g)
SKU: CD97 | Barcode: 810666001680
Origin: Romania
TDS to EC Conversion Guide
TDS (ppm) readings can be converted to electrical conductivity (µS/cm) using the following common scale factors:
0.5 Factor (500 Scale): 1 ppm = 2.0 µS/cm
0.7 Factor (700 Scale): 1 ppm ≈ 1.43 µS/cm
442 Scale: 1 ppm ≈ 1.43 µS/cm
Applications
Reverse osmosis (RO) system filter verification
Drinking water & tap water quality monitoring
Water conditioning & softener performance testing
Hydroponics nutrient solution monitoring
Aquarium & reef tank water quality
Science education & classroom labs
Pool & spa water testing
Probe Care & Maintenance
EC/TDS electrodes can develop mineral and nutrient buildup over time. To maintain accuracy and extend probe life:
Always rinse the probe in fresh tap or deionized (DI) water after every use
Recalibrate periodically using M10080B 800 ppm calibration solution sachets
Store the pen with the protective cap on to prevent probe damage
Why Milwaukee Instruments?
Milwaukee Instruments is trusted worldwide by water treatment professionals, hydroponics growers, aquaculture specialists, and educators. The CD97 combines Milwaukee’s proven build quality, factory-calibrated accuracy, and long battery life in one of the most cost-effective TDS pen testers on the market.
