Milwaukee ph51 Waterproof PH Tester Pen

SKU: 07145


In stock

This Milwaukee pH Tester Pen is one of our most accurate low cost, rugged and reliable pH testers on the market featuring the ability to easily replace the probe providing for years of carefree use. The tester pens simple 2 point manual calibration is simple-to-use. Ideal for use in aquariums, hydroponics, horticulture, pools and many other applications.
The Milwaukee pH51 pH Tester Pen offers:


The Milwaukee pH51 tester pen is accurate to ±0.1 pH and is easy to read.
With easy 2 point manual calibration, this pH tester is quickly calibrated to an accuracy of much more expensive meters. Simple design and rugged, it brings great value for any application. Why guess at your readings using litmus paper when you can have guaranteed accurate, digital LCD results.


The tester pen comes with a replaceable pH probe with a double junction probe designed for longer life.


The probe is double junction allowing quick, accurate pH readings and response times.


No more worries about dropping your tester while measuring. The Milwaukee pH51 is waterproof to IP65.


At just 3.5 ounces, the pH51 is easy to handle at up to half the weight of other testers.


A large LCD screen makes reading results easy while calibrating or reading your measurement. This takes the takes the guess work out of litmus paper.


  • Fast easy to read results with large digital LCD readout.
  • Extreme pH accuracy to ±0.1 pH with a pH range (0.0 pH to 14.0 pH).
  • Lightweight and portable.
  • Easy measurement: just place the probe in the sample, gently stir, wait for the stability indication to show a stable reading and then freeze the reading.
  • Simple manual one or two-point calibration.
  • Gel-filled, double junction pH electrode for low maintenance and high performance.
  • Fully waterproof to IP65.
  • Over 1500 hours of continuous battery life (batteries included).
  • Replaceable pH electrode.


All pH sensors have a limited life and response time gets longer with age. Properly maintaining your pH pen tester will give you fast, accurate results for longer.
Here are our top four tips.
1. Always store with the cap full of buffer or pH probe refill & storage solution not water.
2. Clean the Tester regularly by soaking in cleaning solution.
3. Calibrate after cleaning and/or storage before testing to adjust for changes in the pH sensor.
4. Gently stir the Tester in the sample for a faster result.


We recommend registering your product with Milwaukee here to take advantage of their Warranty service.
Milwaukee warrants it’s instruments to be free of manufacturing defects as follows: bench meters for 3 years, portable and pocket testers for 2 years and electrode/sensors for 6 months (unless otherwise specified).
The warranty period commences from the original date of sale to the user. The warranty applies when the product is used under normal conditions and in accordance with the operating limitations and prescribed maintenance procedures.
Milwaukee reserves the right to make improvements in design, construction and appearance of its products without advance notice.

Instrument service

Warranty and non-warranty service are performed by our technicians in Milwaukee headquarters.
All items must have a Return Goods Authorization (RGA) number before returning the goods.
This number can be obtained by contacting the Milwaukee technical service department at:
Weight 0.2000 kg


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