{"product_id":"hanna-hi98331-direct-soil-ec-tester","title":"Hanna Soil Test Direct Soil EC \u0026 Temperature Tester HI98331","description":"\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eThe Hanna Soil Test HI98331 is a portable electrical conductivity and temperature tester designed for direct measurement in moist soil and soilless growing media. Its stainless-steel penetration probe eliminates the need to prepare a soil slurry for routine testing, making it easier to monitor soluble-salt trends throughout a crop cycle.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eThe HI98331 is particularly useful for greenhouse crops, indoor gardens, nurseries, container plants, tropical houseplants, coco coir, peat-based mixes, and rockwool. By monitoring direct EC consistently, growers can identify increasing salt levels, compare fertilizer practices, and recognize developing root-zone problems before visible plant stress becomes severe.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan\u003eKey Benefits\u003c\/span\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eDirect media testing:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Insert the penetration probe into moist growing media without preparing a liquid slurry.\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eMeasures EC and temperature:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Displays electrical conductivity and temperature for convenient root-zone monitoring.\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eStainless-steel penetration probe:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Designed for insertion into soil, coco coir, peat mixes, rockwool, and similar media.\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eAutomatic temperature compensation:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Applies a fixed 2% per °C coefficient to compensate EC readings for temperature.\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eAutomatic calibration:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Performs a one-point calibration using a 1413 µS\/cm conductivity standard.\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eSimple operation:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Compact design and single-button control make routine testing straightforward.\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eRepeatable crop monitoring:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Helps growers develop baseline EC ranges for their plants, media, and irrigation practices.\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003ePortable design:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Suitable for greenhouse benches, indoor gardens, nurseries, raised beds, containers, and field sampling.\u003c\/span\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cspan\u003eWhat the HI98331 Measures\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eElectrical conductivity indicates the ability of moisture within the growing media to conduct an electrical current. Conductivity generally increases as the concentration of dissolved fertilizer salts and other ions rises.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eThe HI98331 measures direct media EC. It does not measure individual nutrients, identify which salts are present, or directly report fertilizer concentration in ppm.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan\u003eDirect EC Versus Nutrient-Solution EC\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eA direct measurement taken in growing media is not equivalent to measuring the EC of a hydroponic reservoir or freshly mixed nutrient solution.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eDirect EC is influenced by:\u003c\/span\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003eMoisture content\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eMedia composition\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eWater-holding capacity\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eFertilizer distribution\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eTesting depth\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eTime since irrigation\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eDrainage and evaporation\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003ePrevious fertilizer or salt accumulation\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eResults will also differ from saturated-media extract, pour-through, and dilution or slurry testing methods. There is no universal conversion that accurately translates every direct reading into pore-water EC or nutrient-solution strength.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eFor meaningful results, compare readings taken from the same type of media using the same testing method and moisture conditions.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan\u003eEC Specifications\u003c\/span\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eEC range:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e 0 to 4000 µS\/cm\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eAlternate EC range:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e 0.00 to 4.00 mS\/cm or dS\/m\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eResolution:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e 1 µS\/cm or 0.01 mS\/cm\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eAccuracy from 0 to 2000 µS\/cm:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e ±50 µS\/cm\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eAccuracy from 2000 to 4000 µS\/cm:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e ±300 µS\/cm\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eAccuracy from 0.00 to 2.00 mS\/cm:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e ±0.05 mS\/cm\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eAccuracy from 2.00 to 4.00 mS\/cm:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e ±0.30 mS\/cm\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eCalibration:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Automatic one-point calibration\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eCalibration standard:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e 1413 µS\/cm or 1.41 mS\/cm\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eTemperature compensation:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Automatic with a fixed 2% per °C coefficient\u003c\/span\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cspan\u003eTemperature Specifications\u003c\/span\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eTemperature range:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e 0.0 to 50.0°C \/ 32.0 to 122.0°F\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eTemperature resolution:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e 0.1°C \/ 0.1°F\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eTemperature accuracy:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e ±1°C \/ ±1.5°F\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eTemperature sensor:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Integrated into the penetration probe\u003c\/span\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cspan\u003ePenetration Probe\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eThe fixed HI73331 stainless-steel penetration probe is designed for direct insertion into moist media. Its narrow profile allows growers to test within the active root zone while minimizing disruption to containers and planted beds.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eCreate a pilot hole before testing compacted or coarse media. Do not force, pry, twist, or rock the probe through stones, dense roots, bark pieces, or other hard materials. Excessive sideways pressure may bend or damage the probe.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan\u003eHow to Calibrate\u003c\/span\u003e\u003c\/h3\u003e\n\u003col start=\"1\"\u003e\n\u003cli\u003e\u003cspan\u003eInspect the probe and remove any visible soil or fertilizer residue.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eRinse the probe with distilled or deionized water.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eDry the probe before placing it into the calibration standard.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003ePour fresh 1413 µS\/cm conductivity standard into a clean container.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eImmerse the required portion of the probe in the standard.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eEnter calibration mode and allow the tester to recognize the standard.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eWait for automatic calibration to complete.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eRinse and dry the probe before returning to soil testing.\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ol\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eNever pour used calibration solution back into its original container. Calibration solution is sold separately unless specifically included in a retailer-created bundle.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan\u003eHow to Test Soil or Soilless Media\u003c\/span\u003e\u003c\/h3\u003e\n\u003col start=\"1\"\u003e\n\u003cli\u003e\u003cspan\u003eChoose a representative testing location within the plant’s active root zone.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eConfirm that the media is evenly moist. Dry media will not provide the continuous moisture path required for dependable EC measurement.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eWhen possible, test near field capacity after excess irrigation water has drained.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eUse a ruler, probe guide, or auger to create a pilot hole and establish a consistent testing depth.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eInsert the stainless-steel probe straight into the media.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eAvoid twisting or applying sideways pressure.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eAllow the displayed EC and temperature readings to stabilize.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eRecord the result, testing depth, media type, and time since irrigation.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eTake readings from at least three representative locations and calculate the average.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eRinse and dry the probe after testing.\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ol\u003e\n\u003ch3\u003e\u003cspan\u003eBest Practices for Repeatable Results\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eHanna recommends testing when the media is close to field capacity. As a general guideline, this may be approximately 15 minutes after irrigation, once water has drained from larger pores and moisture has become more evenly distributed.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eFor useful trend data:\u003c\/span\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003eTest the same media formulation each time.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eMeasure at the same depth.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eTest at a consistent interval after irrigation.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eTake multiple readings and average the results.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eKeep fertilizer concentration and irrigation records.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eCompare each crop against its own established baseline.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eNote plant appearance, runoff EC, and environmental conditions.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eAvoid comparing direct readings with unrelated charts based on different extraction methods.\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eConsistency is more valuable than relying on a universal “ideal” number.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan\u003eInterpreting Results\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eA rising direct EC trend may indicate increasing fertilizer concentration, insufficient runoff, uneven irrigation, or accumulated mineral salts. A falling trend may indicate reduced fertility, heavy leaching, lower fertilizer inputs, or increased nutrient uptake.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eAlways interpret the reading alongside:\u003c\/span\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003ePlant species and growth stage\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eMedia composition\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eMoisture level\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eIrrigation frequency\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eFertilizer program\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eRunoff percentage\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003ePlant appearance and vigor\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003ePrevious readings from the same crop\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eDo not make a major fertilizer or flushing adjustment based on one isolated measurement.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan\u003eCare and Maintenance\u003c\/span\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003eRinse the stainless-steel probe after every use.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eRemove soil and fertilizer residue before it dries.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eDry the probe before storage.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eAvoid abrasive pads, harsh chemicals, and metal tools.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eDo not bend or pry with the penetration probe.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eCalibrate regularly with fresh conductivity standard.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eReplace calibration standard if it becomes cloudy or contaminated.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eStore the tester within its specified environmental range.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eFollow Hanna’s instructions when replacing the battery.\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eUnlike a glass pH electrode, this conductivity probe does not require pH electrode storage solution.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan\u003eAdditional Features\u003c\/span\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003eEasy-to-read digital display\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eSingle-button operation\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eSelectable automatic shutoff after 8 or 60 minutes\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eAutomatic shutoff can also be disabled\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eReplaceable CR2032 battery\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eApproximately 100 hours of continuous battery operation\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eOperating environment up to 95% relative humidity, non-condensing\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cspan\u003eWhat Is Included\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eThe Hanna HI98331 is supplied with:\u003c\/span\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003eHI98331 Soil Test conductivity tester\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eFixed HI73331 stainless-steel penetration probe\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eCalibration screwdriver\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eBattery\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eOperating instructions\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eConductivity calibration solution may be required separately.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan\u003eImportant Limitations\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eThe HI98331 measures EC and temperature. It does not measure soil pH, moisture percentage, individual nutrient concentrations, TDS in ppm, or specific fertilizer elements.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eBecause moisture content strongly affects direct conductivity measurements, dry-media readings should not be compared with readings taken near field capacity. Measurements from different media types or different extraction methods are also not directly interchangeable.\u003c\/span\u003e\u003c\/p\u003e","brand":"Hanna Instruments","offers":[{"title":"Default Title","offer_id":32087673101,"sku":"HI98331","price":144.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1298\/4199\/products\/HANNA_-GroLine-Soil-Test-Direct-Soil-EC-Tester-Hanna-Instruments-1674002324.jpg?v=1674002326","url":"https:\/\/www.gardensupplyguys.com\/products\/hanna-hi98331-direct-soil-ec-tester","provider":"GARDEN SUPPLY GUYS","version":"1.0","type":"link"}