



Hanna Instruments HI-991003 Extended Range pH Meter with pH/ORP electrode & °C sensor
HI-991003 is a lightweight, durable, portable, pH/ORP and temperature meter for pH and ORP measurements encountered in recreational waters (swimming pools and spas), plating baths, water treatment, manufacturing and environmental testing applications.
The meter is supplied with the HI-12973 rugged probe protected with a titanium body specially designed for use on this meter.
Main features:
- Simultaneous pH, ORP and temperature measurements on a large three-line LCD display
- Automatic pH calibration at one or two points within two memorised buffer sets (standard or NIST)
- User friendly two button design
- Selectable temperature unit (°C)
- Electrode condition indicator
- mV of pH measurement for electrode check
- HI-12973 dedicated pH/ORP with integral temperature sensor
- Probe quick connect system
- Battery life indication and low battery detection
- Keystroke confirmation tone
- Auto-off function
- Waterproof casing IP67
Meter is supplied complete with:
- HI-12973 Preamplified pH/ORP with internal temperature sensor, DIN connector and 1m cable
- pH 4.01 & 7.01 buffer sachet
- HI-700601 General electrode cleaning solution (2 sachets)
- 100mL beaker
- Alkaline batteries: 1.5V AAA x3
- Rugged carrying case
- Calibration certificate of meter
- Calibration certificate of probe
- Instruction manual
Available to buy separately:
- Shockproof rubber boot:
- HI-710028 Orange
- HI-710029 Blue
- HI-710030 Green
The pH range is limited from 0 to 13 pH and the temperature range from 0 to 80 °C (32 to 176 °F) using HI-12973 probe.
Specifications
| pH Range | -2.00 to 16.00 pH |
| Temperature Range | -5.0 to 105.0°C |
| ORP Range | ±1999 mV |
| mV | ±825 mV (pH-mV) |
| pH Resolution | 0.01 pH |
| Temperature Resolution | 0.1°C |
| ORP Resolution | 1mV |
| mV Resolution | 1 mV |
| pH Accuracy | ±0.02 pH |
| Temperature Accuracy | ±0.5°C |
| ORP Accuracy | ±2mV |
| pH Electrode | HI-12973 pre-amplified pH and temperature probe with titanium body, Quick Connect DIN connector and 1 m (3.3') cable (included); please note: HI-12973 is limited to be used from 0 to 13 pH and from 0 to 80° |
| Battery Type / Life | 3 x 1.5V AAA / approx. 1400 hours of continuous use |
| Environment | 0 to 50°C (32 to 122°F); RH max 100% |
| Dimensions | 154 x 63 x 30 mm |
| Weight | 196 g |
| Case Protection Rating | IP67 |
| Electrode included | HI-12973 pre-amplified pH/ORP with internal temperature sensor, DIN connector and 1m cable |
Downloads

Frequently Asked Questions
Clear answers to help you choose the right water testing solution with confidence
Which brands of water testing kits do you supply?
Do you provide kits for both home and professional use?
Yes — whether you’re a pool or spa owner, aquarium keeper, utility company, or a university laboratory, we have the right solution for your needs.
Can I arrange servicing or calibration for my photometer?
Absolutely. We also provide servicing and calibration to keep your photometers accurate and reliable.
How quickly do you dispatch orders?
Orders placed before 2:30 pm (Monday–Friday) are dispatched the same day. We also ship on Saturdays for your convenience.
Which couriers do you use for delivery?
We deliver through UPS, DPD, and Royal Mail. You can also choose to upgrade to next-day delivery at checkout.
What is your return policy?
We accept returns within 14 days of delivery provided the items are unused, in their original packaging, and in resalable condition. Please contact our team before returning any items.
Can I place bulk or business orders?
Yes, we welcome bulk, trade, and institutional orders. For tailored pricing or large quantities, please get in touch with us directly.
How can I get help if I’m unsure which kit to buy?
You can call us at 📞 +44 (0)115888 2726 and our team will guide you in choosing the most suitable kit for your needs.