Hanna Instruments HI-9812-51 pH EC TDS Temperature Portable Meter
The HI-9812-51 and HI-9811-51 series of meters are pH/EC/TDS instrumentation for agriculture, greenhouse and hydroponics applications.
These meters feature a large LCD which displays either pH, EC, TDS or temperature readings along with tutorial instructions. The pH readings are displayed with a 0.1 resolution and an accuracy of ±0.1 pH while the EC and TDS readings are displayed with a 10 m/s/cm and 10 ppm (mg/L) resolution and 2% full scale accuracy. Please select the meter with the range you require for your testing.
The temperature correction coefficient (β) is fixed at 2%/°C and allows for automatic temperature compensated measurements of EC and TDS. These meters are calibrated manually to a single point with the use of two trimmers. pH is calibrated to pH 7.01 while EC/TDS is calibrated to either 1.41 mS/cm (1413 µS/cm) or 1500ppm. The LCD screen has battery life indicator as well as on-screen tutorial messages.
No probe changes are required when switching your measured parameter between pH, conductivity and TDS. These multiparameter meters reduced the number of instruments required for daily water quality analysis.
The supplied probe on all models feature a polypropylene body, amplified pH electrode with a built-in EC/TDS and temperature sensors. The amplifier for the pH electrode prevents interference from humidity and electrical noise from common sources including the motors, ballasts or pumps.
HI-1285-51 probe
The HI-9811-51 and HI-9812-51 are supplied with the HI-1285-51 pH/EC/TDS/temperature probe. The pH, EC, TDS, and temperature sensor are housed in a single body that connects to the meter with a DIN connector.
Amplified pH electrode
The pH electrode circuit has a built in amplifier that will reduce the effects of electrical noise on the high impedance pH measurement. Examples of sources of electrical noise include motors, ballasts, and pumps which are common in greenhouses.
Amperometric EC/TDS sensor
The EC/TDS readings are performed by an amperometric sensor. An alternating voltage is applied to the sensor and the amount of current that passes between the two stainless steel pins is dependent upon the amount of salts (fertiliser) present. A greater amount of salt present results in an increase in conductance.
Polypropylene body
The polypropylene body houses all the sensors in a single body design and is durable. The probe is gel filled for maintenance free operation. It does not have to be refilled periodically.
3 sensors in a single probe
Gel filled maintenance free pH electrode
Specifications
| Range | EC | 0 to 1990 µS/cm |
| TDS | 0 to 1990 ppm (mg/L) | |
| pH | 0.0 to 14.0 pH | |
| Temp | 0 to 60°C | |
| Resolution | pH | 0.1 pH |
| EC | 10 µs/cm | |
| TDS | 10 ppm (mg/L) | |
| Accuracy | pH | ±0.1 pH |
| EC | ±2% F.S. | |
| TDS | ±2% F.S. | |
| Temp | ±1°C | |
| TDS Conversion Factor | 0.5 ppm (mg/L) = 1 µS/cm | |
| pH Calibration | manual, 1 point through offset trimmer | |
| EC/TDS Calibration | manual, 1 point through slope trimmer | |
| EC/TDS Temperature Compensation | automatic from 0 to 70°C with β = 2% /°C | |
| Probe | HI 1285-51 pH/EC/TDS/Temperature, polypropylene body, pre-amplified multiparameter probe with internal temperature sensor, 8-pin DIN connector and 1m cable included | |
| Battery Type / Life | 9V / approximately 450 hours of continuous use | |
| Environment | 0 to 50°C; RH 100% | |
| Dimensions / Weight | 145 x 80 x 36mm / 230g | |
| Ordering Information | HI-9811-51 and HI-9812-51 are supplied with HI-1285-51 multiparameter probe, HI-70007 pH 7.01 calibration solution sachet, HI-70032 1382 ppm (mg/L) calibration solution sachet, HI-70031 1413 µS/cm calibration solution sachet, HI-700661 electrode cleaning solution sachets x 2, 9v battery x 1, instructions and rugged carrying case. | |
| Accessories | HI-710007 blue shockproof rubber boot; HI-710008 orange shockproof rubber boot |
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.