Bluelab pH Pen

Bluelab pH Pen

SKU #: HGC716480
Bluelab Brand Product

Availability: In stock

Lead time: Ships in 24-48 Hours

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Bluelab pH Pen

The ultimate handy solution for measuring pH and temperature!

Plants get their nutrient from minerals but they can only get all the right minerals they need if certain conditions are right. Think of nutrients like a lock. pH is the key. A key factor that affects food uptake is whether your solution is acid or alkaline. We measure this in pH.

The Bluelab pH Pen also measures the temperature of the solution, as root health is vital to the success of a crop. Temperature affects the growth rate and structure of a plant so a solution temperature of 18 - 22˚C or 65 - 72˚F is recommended.

The hand held pH pen provides a compact quick and handy way to manage the success of your crop to ensure maximum uptake of nutrients.

Teamed with our Bluelab ppm / EC Pen, you have a handy, convenient and accurate system for ensuring optimum plant growth and health


  • Measures pH and temperature
  • Selectable units for temperature
  • Backlit LCD display
  • Double junction probe (not replaceable)
  • Successful pH calibration indicator
  • Hold reading function
  • Low battery indicator
  • Fully waterproof
  • Auto off function
  • Automatic temperature compensation
  • 1 x AAA alkaline battery included














What is pH?

pH (short for potential Hydrogen) is the measurement of acidity and its opposite, alkalinity in a solution. Neutral pH is 7.0 pH. Acidity measures below seven pH (7.0pH) with alkalinity measuring above it (7.0pH).

Why is it important to measure pH?

It is important to maintain a hydroponic nutrient solution at a pH level where the elements in the nutrient solution are consistently available to the plant. If the solution is too acidic or too alkaline it can cause “lock up” – a situation which restricts certain elements essential for growth from being absorbed by the root structure. Deficiencies in the required elements become apparent in the plants growth and can lead to crop failure. Additionally the pH of the water we drink is crucial to our health, the pH of a swimming pool is important, not only for our skin and eyes, but also for the efficiencies of sanitizers and pool equipment. Again the pH of the water a fish lives and breeds in is critical to its existence as certain species require a particular pH to survive. The elements we add to a solution will either increase or decrease the solutions pH measurement. Only accurate measurement of the pH level will allow complete control of the outcome

Tech Specs


Weight (lb.)0.4
Height (in.)8.2
Prop 65No
Lead TimeShips in 24-48 Hours
Length (in.)1.9
Width (in.)3.7
Warranty1 Year
UL ListedNo

Bluelab pH Pen Videos

Product Q&A

Bluelab pH Pen Questions & Answers

I am unable to successfully calibrate my pH pen

Possible Reasons:

  • Buffers inaccurate
  • Glassware not clean
  • Glassware aged (glassware will not clean)
  • Probe not hydrated

Possible Solutions:

  • Replace buffers
  • Clean glassware
  • Replace unit
  • Soak probe in water for 24 hours and retest

What if my pH Pen or pH Probe has accidentally dried out?

The pH pen or probe must be 'hydrated' for 24 hours. Place the pH probe or pH pen upright in a small plastic container. Add enough KCl storage solution into the container to cover the pH probe tip. Leave the pH pen or pH probe to soak in the KCl solution for at least 24 hours.

Carry out a calibration to check if the pH pen or pH probe has already suffered permanent damage.

What is KCl storage solution?

KCl storage solution is generally a mixture of Potassium Chloride (KCl) and water. Some brands may contain small amounts of other ingredients.


Customer Reviews 1 item(s)

Good pen, not waterproof
I am on my second pen because the first stopped working properly after a few weeks. The second started acting up as well. I believe the unit is not meant to get wet except the very tip. When water gets into the seam at the top of the unit, it causes a problem. Not a bad pen but I wish it was waterproof.

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