Grow better with GroLine.

Meters and testers designed for hydroponic, aquaponic, and greenhouse growers to get consistently great results.

Hanna GroLine products are the most accurate and easiest to use tools to help you manage your growing nutrients.

Monitor like a scientist. Grow like a professional.

GroLine Hydroponic Nutrients Monitor for pH, EC, TDS, and Temperature - HI981420


24-hour continuous pH, EC/TDS, and temperature monitoring of your nutrient solution.

Our GroLine Monitor is made by growers and scientists alike who are committed to helping you take your growing operation to the next level.

Measure with confidence.

GroLine Waterproof Combo Meter for pH, EC, TDS (ppm) - HI9814


No time to waste.

Start testing faster with Quick Cal mode to perform a single point pH and EC/TDS calibration with one solution.

Higher quality measurements.

With high resolution and high accuracy, your results are more accurate than ever.

Test anywhere, anytime.

Our GroLine Portable Meter is waterproof to withstand your grow environments.

GroLine Waterproof Combo Meter for pH, EC, TDS (ppm) - HI9814
GroLine Waterproof Combo Meter for pH, EC, TDS (ppm) - HI9814

Upgrade to the GroLine Portable Kit

Complete. Start to finish.

Upgrade to the full pH/EC/TDS (ppm) kit and get all the essentials you need to start growing more, now.


Developed to help growers test nutrients often and easily.

Take accurate and reliable nutrient measurements with our portable testers that go where you go.

Simple pH Tester



Take your testing to the next level.

This simple GroLine pH tester makes upgrading from chemical test kits easy.

Waterproof pH Tester



Extended life.

Specialized for hydroponics, this tester goes where you go.

Conductivity & TDS (ppm) Tester



Confidence in your results.

With an adjustable TDS conversion factor, you can ensure that your results are right the first time.


Direct soil measurements, simplified.

See what your roots see.

Direct Soil pH Electrode



No matter the material.

Use with the HI9814 for pH measurements in a variety of soil and soilless media.

Soil Conductivity Tester



Get to the heart of the matter.

The stainless steel electrode makes direct measurements quick.

HALO® Wireless Soil pH Meter



Next level tools for next level growers.

Take direct soil pH and temperature measurements using your smartphone or tablet.


Bring it all together.

GroLine Waterproof Combo Tester for pH, EC, TDS (ppm)


Specialized for hydroponics, this waterproof tester can handle any environment. It's simple, friendly design makes taking conductivity/TDS (ppm) and pH with one device easy and a pH replaceable probe extends the life of our most advanced GroLine pH/EC/TDS (ppm) tester.

More reasons to love GroLine.

Growers all over the world rely on GroLine products to ensure successful crop yields.

"Best Portable Meter"

I have been using this HI9814 daily for about a year now. I will never go back!

-Justin S

Website Review

"This IS the meter for your needs"

Accurate testing is critical to appraising ones water to determine filtration needs. This is the one you want!! pH dead on, PPM/EC true as you can get!

-Brett R.

Website Review

"Love this product"

Absolutely love this product. Very accurate and easy to use. Will recommend this to everyone.

-Luc T.

Website Review


Perfect for testing directly in your soil or other growing media.

Direct Soil and Soilless Media pH Electrode for HI9814


This electrode was created specifically for pH measurements in soil, coco, rockwool, and water. With a built-in temperature sensor and automatic temperature compensation, you can feel confident that your results are right the first time.

Need a Replacement Electrode?

Don't let a broken electrode stop you from testing. Replace with a spare and go. Quick replacements for GroLine testers and portable meters.

Quick Cal makes calibration fast and simple.

One solution to calibrate it all.

You can now calibrate pH and conductivity all at once with a single solution.



Together this equals the most convenient calibration solution for growers.

Simple. Original. Smart.

HALO Wireless Soil pH Meter


Upgrade your portable pH testing experience.

Our newest HALO model lets growers, gardeners, and farmers take direct soil pH measurements using a smart phone or tablet.

Other things to help you get started.

Calibration Solutions


Storage and Cleaning





Providing solutions to the problems growers face every day.

How to Prepare a Soil Slurry

Not sure how to prepare a sample for pH and EC/TDS (ppm) testing? Follow these steps, or watch the video below!

Step 1: Gather your materials. You will need:

  • A container cleaned with distilled or DI water
  • A measuring cup
  • A fresh sample of your soil
  • Distilled or DI water
  • A magnetic stirrer OR a stirring utensil

Step 2: Measure out equal parts of soil and distilled water, ensuring there is a large enough sample to completely submerge your electrode junction.

Step 3: Add soil to the clean container, then add the distilled water.

Step 4: Stir the sample. For best results, use a magnetic stirrer. Make sure all clumps of soil are broken up!

Step 5: Wait 15 minutes for the sample to settle before taking your measurement.

Step 6: Immerse your electrode into the sample and wait for a stable reading.

Hanna Tip: An ideal pH reading is between 5.5 and 7. If you are getting a reading far off from this, there may be a problem with your electrode. Check our pH Electrode Troubleshooting Guide for some common problems and how to fix them.

pH Testing Tips

Clean Regularly.

Depending on the nature of your samples, your pH electrode can become dirty or clogged resulting in slow and faulty readings. Regular cleaning will prolong the life of your electrode.

Calibrate Often.

To ensure your pH measurements are accurate, be sure to calibrate after extended storage, cleaning, and before use. Use fresh buffers that bracket your expected value.

Condition Always.

A dry electrode results in slow, incorrect measurements. Always use proper storage solution and be sure to fully cover the junction.

To learn more, download our pH Best Practices Guide here!

Your pH Electrode

Pick the Right Tip Shape for Your Testing Needs.


A spherical tip is the most common shape for a pH electrode due to it's large surface area.
BEST FOR: aqueous samples and general purpose.


A cone shape makes testing of semi-solids easy.
BEST FOR: direct penetration into semi-solids, emulsions, soil, and slurries.

Flat Tip

The flat tip allows for the direct surface measurement of a sample.
BEST FOR: flat surfaces, skin, leather, and paper.


Finding the right electrode for specific testing can be tough. In order to help, Hanna Instruments has put together a guide, Getting To Know Your pH Electrode.