The Oakton 35425-10 Oakton Multiparameter 35-Series PTTestr 35 is a handheld, waterproof, and dustproof pocket meter that measures pH, conductivity, and temperature and floats, if dropped in liquids. A portable pocket met...

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Product Review

The Oakton 35425-10 Oakton Multiparameter 35-Series PTTestr 35 is a handheld, waterproof, and dustproof pocket meter that measures pH, conductivity, and temperature and floats, if dropped in liquids. A portable pocket meter is commonly used to measure the pH of substance in hydroponics, agriculture, industrial process checks, water treatment, and swimming pools. This meter features ATC for accurate readings in fluctuating temperatures, and push-button calibration capabilities for a wide range of results. It has stainless steel, pin-type conductivity sensors for durability and compatibility with a wide variety of samples. The meter’s waterproof and dustproof housing has IP67-rating for protection against solid objects or liquids. The testr has a long-lasting sensor with Polyvinylidene Fluoride (PVDF)-protected reference junction with polymer gel for longer lifespan. The meter has a large, upright, dual-line LCD screen for ease of viewing, a hold function which freezes readings for recording, and an auto shut-off to extend the life of the batteries. It has a click-lock battery cover for battery access to replace batteries without tools.

The 35425-10 pocket meter has ATC from 0 to 50 degrees C (32 to 122 degrees F), or manual ability, and an operating temperature range of 0 to 50 degrees C (32 to 122 degrees F), resolution 0.1 degree, + or - 0.5 degrees C (+ or - 0.9 degrees F). It has 1-point temperature, 1-point salinity, 3-point TDS, 3-point conductivity, and 5-point pH calibration capability range. pH range is 0.0 to 14.0, resolution 0.1, accuracy + or - 0.1. TDS range 0 to 99.0 ppm; 100 to 999 ppm, 1.00 to 10.00 ppt, resolution 0.1 ppm, 1 ppm, 0.01 ppt, accuracy + or - 1% full-scale. Conductivity range 0 to 200 μS; 201 to 2000 μS, 2.01 to 20.00 mS, resolution 0.1 μS, 1.0 μS, 0.01 mS, accuracy + or - 1% full-scale. Salinity range 0 to 10.00 ppt, 0.1 ppm, 1 ppm, resolution 0.01 ppt, 0.01%, accuracy 1% full-scale. Its dimensions are 1.25 (w) x 6.5 (h) inches (3.8 x 16.8 cm) and it weighs 3.25 ounces. The testr works with four 1.5-V alkaline batteries (not included) for up to 250 hours of continuous use (Eveready A76 or LR44 replacements).

pH testers measure the acidity or alkalinity of a substance and are commonly used by researchers, manufacturers, and hobbyists in aquaculture, agriculture, hydroponics, wine-making, and water-testing and for scientific applications. Conductivity meters measure the ability of a material or solution to conduct an electrical current. TDS such as salts and minerals contribute to the conductivity of a solution. A TDS meter measures the conductivity and converts it to a TDS reading.

Oakton Instruments manufactures an array of scientific instruments for research, industrial, and educational uses. Since 1991, Oakton has distributed a wide variety of instruments such as meters, electrodes, and transmitters. Oakton is based in Vernon Hills, IL, and has facilities in Europe, Asia, and China.

What’s in the Box?

  • Meter 35425-10


  • Push-button calibration capabilities for a wide range of results
  • Automatic Temperature Compensation (ATC) for accurate readings in fluctuating temperatures
  • Stainless steel pin-type conductivity sensors for durability and compatibility with a wide variety of samples
  • Waterproof, dustproof housing is Ingress Protection (IP) 67-rated, for protection against solid objects or liquids
  • Large, upright, dual-line LCD display screen for ease of viewing, and for display of indicators

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