GroStar GS1 pH Pen

Know Your Numbers Before Your Plants Tell You the Hard Way

By the time a pH imbalance shows up as yellowing leaves or stalled growth, you've usually already lost time you can't get back — and guesswork or low-grade meters tend to catch problems only after they've taken hold.

The GroStar GS1 closes that gap with lab-grade measurement in a pen built specifically for growers. Its premium probe technology delivers high accuracy and durability with minimal upkeep, while a large 3-color backlit screen keeps your readings clear in any light, in or out of the tent.

It's also built to last where it counts: the double-junction probe is replaceable, so a worn sensor doesn't mean replacing the whole instrument, and an IP67 waterproof rating means a splash near the reservoir won't end your meter's career.

Key Features & Benefits

• Measures pH and temperature — gives you the two readings that matter most for nutrient uptake, in one easy check.
• Replaceable double-junction probe — lets you swap a worn sensor (GS1-E) instead of replacing the whole pen when it reaches end of life.
• Large 3-color backlit screen — keeps readings sharp and easy to read in dim grow rooms or bright daylight alike.
• IP67 waterproof rating — stands up to splashes and spills around reservoirs and feeding stations without flinching.
• Easy-to-use design with fast calibration — gets you from unboxing to accurate readings quickly, with automatic temperature compensation built in.
• Complete kit included — comes with a 2-year instrument warranty, 1-year probe warranty, pH 7 and pH 4 calibration solutions, KCL storage solution, lanyard, and manual.

Who Should Use the GroStar GS1

The GS1 suits growers who want a dependable, lab-grade pH and temperature pen for nutrient solutions — without the bulk or expense of a full benchtop instrument, and with a replaceable probe that keeps long-term costs down.

Choosing the Right GroStar Pen for Your Setup

GroStar's pen lineup is built around what you need to measure: the GS1 covers pH and temperature, the GS2 adds a soil-rated spear probe, the GS3 reads EC/PPM and temperature, and the GS4 combines all of it in one 5-in-1 tool. If you're only tracking solution pH, the GS1 keeps things simple without paying for capabilities you won't use.

Frequently Asked Questions

What does the GS1 measure?

It measures pH and temperature, with automatic temperature compensation built in so your pH readings stay accurate as solution temperature shifts.

Can I replace the probe if it wears out?

Yes — it uses a replaceable double-junction probe (GS1-E), so you can swap in a fresh sensor instead of discarding the whole pen at end of life.

What's included in the box?

It ships with pH 7 and pH 4 calibration solutions (50ml each), a KCL storage solution, a lanyard, and a user manual, alongside a 2-year instrument warranty and 1-year probe warranty.

Is it safe to use around water and nutrient solution?

Yes — it carries an IP67 waterproof rating, so splashes near reservoirs and feeding stations won't damage it.

How is it powered?

It runs on AAA batteries with an auto-off function to help conserve battery life between uses.