

Hanna Instruments HI-9813-51 pH/EC/TDS and temperature Portable Meter
HI 9813-51 is a versatile, water resistant multiparameter portable meter specifically designed for agriculture, hydroponics, greenhouses, and nurseries. It features an extra large LCD that clearly displays the parameter being measured as well as calibration instructions.
Portable pH/EC/TDS/Temperature meter
This meter features 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 0.01 mS/cm and 1ppm (mg/L) resolution and 2% full scale accuracy.
The EC range of both meters is from 0.00 to 4.00 mS/cm and TDS is from 0 to 1999ppm.
The temperature correction coefficient (β) is fixed at 2%/°C and allows for automatic temperature compensated measurements of E and TDS.
This meter is 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 1.41mS/cm or 1500ppm. The LCD screen has batter life indicator as well as on-screen tutorial messages. No probe changes are required when switching your measured parameter between pH, conductivity and TDS.
This multiparameter meter reduces the number of instruments required for daily water quality analysis. The supplied probe 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 from motors, ballasts or pumps.
Key features
- Waterproof
- Automatic Temperature Compensation
- Simple calibration
- Low battery indicator
- Fast response multi-parameter probe
Supplied with
- HI-1285-51 multi-parameter probe
- HI-70007 pH 7.01 calibration solution sachet
- HI-70442 1500 ppm (mg/L) calibration solution sachet
- HI-70031 1413 µS/cm calibration solution sachet
- HI-700661 electrode cleaning solution sachets (2)
- Battery and instructions
- Rugged carrying case
- *Orange rubber boot sold separately - HI-710008; blue boot – HI-710007
About the HI-1285 series probes
The HI-9813-51 and HI-9813-61 are supplied with a polypropylene body 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.
Features
3 sensors in a single probe
Amplified pH electrode – The pH electrode 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 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.
Specifications
| Range - pH | 0.0 to 14.0 pH |
| EC | 0.00 to 4.00 mS/cm |
| TDS | 0 to 1999 ppm (mg/L) |
| Temperature | 0.0 to 60.0°C |
| Resolution - pH | 0.1 pH |
| EC | 0.01 mS/cm |
| TDS | 1 ppm (mg/L) |
| Temperature | 0.1°C |
| Accuracy (@20°C/68°F) - pH | ±0.1 pH |
| EC | ±2% F.S. mS/cm |
| TDS | ±2% F.S. ppm |
| Temperature | ±0.5°C |
| TDS Conversion Factor | 0.56 to 0.78 ppm = 1 µS/cm (according to TDS 442 curve) |
| pH Calibration | manual, 1 point |
| EC Calibration | manual, 1 point |
| EC/TDS Temperature Compensation | automatic 0 to 70°C with β=2%/°C |
| Probe | HI-1285-51 |
| Battery Type / Life | (1) 9V / approximately 450 hours of continuous use |
| Environment | 0 to 50°C; 100% RH |
| Dimensions / Weight | 145 x 80 x 36 mm/ 230g |

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.