Hanna Instruments

Low Range pH/Conductivity/TDS Combo Pen HI98129 - Hanna

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Waterproof pH, Electrical Conductivity, Total Dissolved Solids, and Temperature Metering Pen

Highly Accurate readings right out of the box! Every HI98129 is professionally calibrated to 7.01 and 10.01pH and 1382ppm.

  • Lightweight
  • Floats
  • Super Accurate
  • Large LCD Display
  • Measures Temperature
  • Replaceable pH Electrode
  • Automatic Shut-off
  • Includes Pocket Clip


Knowing the pH of your reef tank, or the electrical conductivity of your RODI water is a necessity, and Hanna's HI98129 Combo Pen is the perfect all in one solution. The lightweight and portable pen can test pH, conductivity, or TDS (total dissolved solids) in a single pocket-sized device. The HI98129 can also read the temperature and all the readings are ATC (automatic temperature compensated) which means values will be more accurate.

The pH electrode can be changed, meaning that you will not have to throw away the HI98129 after the probe has exhausted. Almost all pH sensing devices will last about a year or so until the electrode needs to be replaced, and traditionally you would need to buy a whole new metering pen, now you do not have to replace the meter! Just replace the pH cartridge that houses the electrode, and the sturdy snap-in connector will hold the electrode in place until the next time you need to replace it. 

Replacement pH Electrode - HI73127 



TDS Range - 0-2000ppm

TDS Resolution - 1ppm

TDS Accuracy - ±2% F.S.

EC Range - 0-3999µS/cm

EC Resolution - 1µS/cm

EC Accuracy - ±2% F.S.

pH Range - 0.0-14.0

pH Resolution - 0.01pH

pH Accuracy - ±0.05 pH

Temperature Range - 32.0°F to 140°F

Temperature Resolution - 0.1°F

Temperature Accuracy - ±1°F

Temperate Readings - °C or °F

Auto Off - 8 Minutes

Dimensions - 6.4" L x 1.6" W x 1.0" H

Warranty - 1 year


Calibration Settings:

EC/TDS Calibration - Single Point (1413 µS/cm, 1382 ppm)

pH Calibration - Two Point (4.01/7.01/10.01)

TDS Conversion Factor - 0.45 to 1.00

Temperature Compensation - pH (automatic) EC/TDS (automatic with β adjustable from 0.0 to 2.4% / °C)


What's Included?

1x HI98129 pH/EC/TDS Metering Pen

1x HI73127 pH Electrode (pre-installed)

More Information
UPC 799331544443
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Product Questions

Hi, where can I find the calibration packets for this product?
Question by: Anthony Lopez on Sep 8, 2020, 7:10 PM
Hey there,
Thank you for reaching out to us! You can find them on the Hanna web site.




Please let me know if you need anything further and take care!
Answer by: Matt Lucero on Sep 9, 2020, 1:39 PM
So since this measures conductivity, does that mean with the proper equation you can calculate your salinity also with this? Would it be more accurate than a refractometer?
Question by: Darrell on Nov 2, 2017, 8:22 AM
Hi Darrell, thanks for reaching out!
Unfortunately the conductivity range of this unit (0-3999µS/cm) if far below that of seawater (5 S/m) which is one million times higher than that of deionized water (~5 µS/cm).
I hope this helps!
Answer by: Nick on Nov 25, 2017, 9:24 AM