Hanna Instruments

Scientific Equipment

HI-99121 Waterproof pH & temperature meter for direct measurement in soil

HI-99121 Waterproof pH & temperature meter for direct measurement in soil

Hanna HI-99121 Waterproof pH & temperature meter for direct measurement in soil

HI-99121 Waterproof pH & temperature meter for direct measurement in soil

Complete with pH electrode
2 year manufacturer warranty
In Stock
£457.00 (exc. VAT) £548.40 (inc. VAT)

The HI-99121 portable pH meter, together with HI-12923 pH electrode, is designed to measure pH in soil or soil slurries.

The HI-99121 is a lightweight, portable pH and temperature meter. It features a two button operation system and is simple to use. It has a waterproof and compact casing, large dual-line display, and automatic pH calibration at one or two points.

HI-99121 Waterproof pH & temperature meter for direct measurement in soil information

Hanna's extended description

Main features

  • Simultaneous pH and temperature measurements on a large dual-line LCD display
  • Automatic pH calibration at one or two points within two memorised buffer sets (standard or NIST)
  • Selectable temperature unit (°C or °F)
  • Electrode condition indicator
  • mV or pH measurement for electrode check
  • HI-12923 dedicated pH probe with integrated temperature sensor
  • Probe quick connect system
  • Battery life indication and low battery detection
  • Keystroke confirmation tone
  • Auto-off function
  • Waterproof casing IP67

  • About Soil pH

    pH is the measure of the hydrogen ion concentration (H+). The pH scale goes from 0 (very acidic) to 14 (basic) with pH 7 being neutral. Soil can be acid, neutral or alkaline.

    Most plants prefer a pH range from 5.5 to 7.5; but some species prefer more acid or alkaline soils. Nevertheless, every plant has a target for optimum growth.

    pH strongly influences the availability of nutrients and the presence of micro-organisms and plants in the soil.

    For example, fungi prefer acidic conditions whereas most bacteria, especially those supplying nutrients to the plants, have a preference for moderately acidic or slightly alkaline soils. In fact, in strongly acidic conditions, nitrogen fixing and the mineralisation of vegetable residual is reduced. Plants absorb the nutrients dissolved in the soil water and the nutrient solubility depends largely on the pH value. Hence, the availability of elements is different at varying pH levels.




    Each plant needs elements in different qualities and this is the reason why each plant requires a particular range of pH to optimise its growth.

    For example, iron, copper and manganese are not soluble in an alkaline environment. This means that plants needs these elements should theoretically be in an acidic type of soil. Nitrogen, phosphorus, potassium and sulphur, on the other hand, are readily available in a pH range close to neutrality.

    Abnormal pH values may increase the concentration of toxic elements for plants. For example, a plant may not tolerate an excess of aluminium ions that may increase under acidic conditions. When pH values are too far from neutral conditions a less permeable and more compact soil may result.

    Different naturally occurring minerals may affect soil pH in the same way.

    Supplied with:

  • HI-12923 pH/temperature probe with conical tip, DIN Connector and 1m cable
  • HI-70004 pH 4.01 buffer (1 sachet)
  • HI-70007 pH 7.01 buffer (1 sachet)
  • HI-700663 cleaning solution for soil deposits (1 sachet)
  • HI-700664 cleaning solution for humus deposits (1 sachet)
  • HI-7051M soil sample preparation solution
  • HI-721319 auger for ground penetration, packed separately in a carton box
  • beaker (1)
  • 1.5 AAA alkaline batteries
  • Instrument quality certificate
  • Electrode quality certificate
  • Instruction manual


  • Din Connection



    Battery powered – Allows use away from a power source. Batteries are included with all battery operated products.

    Optimum pH values for growers


    Orchard plants, vegetables and herbaceous cultivations

    Preferred pH Range

  • 4.5 to 6 pH - potatoes
  • 5 to 6.5 pH – Apples, rice
  • 5.5 to 6 pH – Sweet potatoes
  • 5.5 to 6.5 pH – Pomegranate, melon, soybean, tomatoes, watermelon




  • 5 to 7 pH – Orange
  • 5 to 7.5 pH - Strawberry
  • 5.5 to 7 pH – carrots, egg plant
  • 5.5 to 7.5 pH – cucumber, pumpkin
  • 6 to 7 pH – Apricot, Grapevine, lemon, barley, lettuce, oat, onion, pepper, wheat




  • 6 to 7.5 pH – Cherry , grapefruit, nectarine, peach, pear, plum, bean, Brussels sprouts, peas, spinach, sunflowers
  • 6.5 to 7.5 pH – Artichoke
  • 6 to 8 pH – Walnut, asparagus

  • Garden plants, flowers & house plants

  • Optimum growing pH between 4.5 and 8.
  • Specifications

    Specifications list

    Specifications

    pH Range -2.00 to 16.00 pH
     Temperature Range -5.0 to 105.0°C / 23.0 to 221.0°F
    pH Resolution 0.01 pH
     Temperature Resolution 0.1°C / 0.1°F
    pH Accuracy ±0.02 pH
     Temperature Accuracy ±0.5°C (up to 60°C), ±1°C (outside);
    ±1.0°F (up to 140°F), ±2°F (outside)
    pH Calibration automatic, 1 or 2 point with 2 sets of memorised buffer values
    (pH 4.01 / 7.01 / 10.01 or pH 4.01 / 6.86 / 9.18)
    Temperature Compensation Automatic, -5 to 105°C (23 to 221°F)
    pH Electrode HI 12923 preamplified pH and temperature probe with conical tip,
    DIN connector and 1 m (3.3') cable (included) - The HI-12923 is limited to be used from 0 to 12 pH and from -5 to 70°C
    Battery Type / Life 3 x 1.5V AAA / approx. 1400 hours of continuous use:
    auto-off after 8 minutes of non-use
    Environment 0 to 50°C (32 to 122°F); RH max 100%
    Dimensions 154 x 63 x 30 mm (5.9 x 3.1 x 1.4")
    Weight 196g
    Case ingress protection rating IP67

    Downloadable Manuals

    Manuals

    Download PDF

    Product Literature

    literature - PDF

    Hanna Instruments Literature

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