{"product_id":"hanna-groline-ph-4-01-calibration-buffer","title":"Hanna GroLine pH 4.01 Calibration Buffer","description":"\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eHanna GroLine pH 4.01 Calibration Buffer is a high-quality, NIST-traceable solution formulated for accurate calibration of compatible pH testers, portable meters, monitors, and controllers. Designed for hydroponics, aquaponics, greenhouses, horticulture, and laboratory testing, it provides a reliable acidic reference point for measuring nutrient solutions, irrigation water, growing-media slurries, and other aqueous samples.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eThe buffer has an accuracy of ±0.02 pH at 25°C and is manufactured under controlled conditions using high-purity salts, deionized water, certified balances, Class A glassware, and certified thermometers. Its dye-free formulation helps prevent staining or contamination of the pH electrode’s reference junction.\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\u003eAccurate pH 4.01 reference:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Provides a dependable acidic calibration point for compatible pH instruments.\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eNIST-traceable formulation:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Values are traceable to National Institute of Standards and Technology Standard Reference Materials.\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eTechnical-grade accuracy:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Rated at ±0.02 pH at 25°C.\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eProfessional manufacturing controls:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Produced using high-purity ingredients and calibrated laboratory equipment.\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eDye-free solution:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Contains no added colorants that could stain or contaminate sensitive electrode components.\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eTwo-point calibration support:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Pairs with pH 7.01 buffer for accurate calibration across the acidic growing range.\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eBroad meter compatibility:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Suitable for Hanna Instruments and other pH meters designed to recognize pH 4.01 buffer.\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eHorticultural applications:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Ideal for meters used with hydroponic reservoirs, aquaponics, irrigation water, fertilizer solutions, soil slurries, and growing media.\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eMultiple packaging options:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Available variants accommodate occasional testing, routine maintenance, and higher-volume calibration programs.\u003c\/span\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cspan\u003eProduct Specifications\u003c\/span\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eNominal Buffer Value:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e pH 4.01\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eAccuracy:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e ±0.02 pH at 25°C\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eTraceability:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e NIST-traceable\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eFormulation:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Technical calibration buffer\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eColorants:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Dye-free\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eRecommended Use:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Acidic calibration point for compatible pH meters\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eManufacturing Standards:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Produced using high-purity salts, deionized water, certified balances, Class A glassware, and temperature-controlled equipment\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cspan\u003eApplications:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Hydroponics, aquaponics, greenhouse production, horticulture, irrigation testing, soil and media testing, and laboratory measurements\u003c\/span\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cspan\u003eWhy Calibrate With pH 4.01 Buffer?\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eA pH meter calculates sample values by comparing the electrode’s response with known reference solutions. Routine calibration corrects for gradual changes caused by electrode aging, contamination, dehydration, temperature exposure, and repeated use.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eThe pH 4.01 buffer establishes the acidic calibration point commonly used for hydroponic and horticultural measurements. Because most nutrient solutions operate below neutral pH, calibrating with both pH 7.01 and pH 4.01 helps verify meter performance across the range growers are most likely to measure.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eA single-point calibration at pH 7.01 may be suitable for routine checks, but a two-point calibration generally provides greater confidence when measuring acidic nutrient solutions.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan\u003eTwo-Point Calibration\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eFor meters that support two-point calibration, pH 4.01 is commonly used with pH 7.01:\u003c\/span\u003e\u003c\/p\u003e\n\u003col start=\"1\"\u003e\n\u003cli\u003e\u003cspan\u003eInspect the electrode for residue, salt deposits, or damage.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eClean the electrode if necessary.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eHydrate a dry electrode in proper storage solution before calibration.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003ePour fresh pH 7.01 buffer into a clean calibration container.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eRinse the electrode with purified water and gently blot away excess droplets.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eCalibrate the meter at pH 7.01 according to its instructions.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eRinse the electrode again.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003ePlace it into a fresh portion of pH 4.01 buffer.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eAllow the reading to stabilize and complete the second calibration point.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eRinse the electrode before testing the sample.\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ol\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eSome instruments specify a different calibration sequence. Always follow the instructions supplied with the meter.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan\u003eCalibration Best Practices\u003c\/span\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003eUse fresh buffer for every calibration session.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003ePour only the amount needed into a clean container.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eNever pour used buffer back into its original package.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eAvoid placing a dirty electrode directly into a multi-use container.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eRinse the electrode between different calibration standards.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eGently blot the electrode instead of rubbing the glass bulb.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eAllow the buffer and electrode to reach a similar temperature before calibration.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eKeep containers closed when they are not in use.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eReplace buffer that appears cloudy, contaminated, discolored, or past its expiration date.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eCalibrate after cleaning the electrode or replacing the probe.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eRecalibrate whenever readings appear slow, unstable, or inconsistent.\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cspan\u003eCalibration Frequency\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eThe appropriate calibration schedule depends on how frequently the meter is used, the required level of accuracy, and the condition of the electrode.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eConsider calibrating:\u003c\/span\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003eBefore critical nutrient or irrigation measurements\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eWeekly when the meter is used frequently\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eEvery few weeks during occasional use\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eAfter cleaning or rehydrating the electrode\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eAfter replacing the electrode\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eAfter extended storage\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eWhen readings become slow or unstable\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eWhenever verification with a known buffer produces an unexpected result\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eCommercial growers, dosing-system operators, and users making frequent nutrient adjustments may benefit from more frequent calibration.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan\u003eTemperature and Buffer Value\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eThe stated pH 4.01 value applies at 25°C. Like other technical buffer solutions, its exact pH changes slightly with temperature.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eCompatible meters with automatic temperature compensation account for temperature’s effect on electrode response. However, temperature compensation does not eliminate the buffer solution’s own temperature-dependent value. For high-accuracy applications, allow the probe and buffer to reach thermal equilibrium and use the temperature reference information supplied with the selected variant when available.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan\u003ePreventing Contamination\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eCalibration buffer can become inaccurate when contaminated by:\u003c\/span\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003eNutrient solution carried on the electrode\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eResidue from cleaning products\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eElectrode storage solution\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eDistilled or deionized rinse water\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eContact with another calibration buffer\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eDust, plant material, or growing-media particles\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eRepeatedly returning used solution to its original container\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eRinse the electrode thoroughly and remove excess rinse water before placing it in the buffer. Use a separate clean container when calibrating from a multi-use package.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan\u003eStorage and Shelf Life\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eStore the buffer tightly closed in a cool, dry location away from direct sunlight, extreme heat, freezing temperatures, and contamination.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eUnopened bottle variants are formulated for an expiration period of up to five years from the date of manufacture. Actual shelf life depends on the selected packaging format, storage conditions, lot number, and printed expiration date.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eUse single-use packaging promptly after opening. Multi-use containers should be closed immediately after dispensing, and the solution should never be used past its marked expiration date.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan\u003eCompatible Equipment\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eHanna GroLine pH 4.01 Calibration Buffer can be used with compatible:\u003c\/span\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003ePocket pH testers\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003ePortable pH meters\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eContinuous pH monitors\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eHydroponic nutrient monitors\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eAutomated pH dosing controllers\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eCombination pH and EC meters\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eReplaceable-electrode testers\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eLaboratory pH meters\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eSoil and growing-media pH testers\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"isSelectedEnd\"\u003e\u003cspan\u003eConfirm that the instrument supports automatic or manual calibration at pH 4.01 before use.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan\u003eImportant Usage Notes\u003c\/span\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003eCalibration buffer is not intended to lower the pH of nutrient solutions.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eDo not add this product to a reservoir or irrigation tank as a pH adjuster.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eDo not use calibration buffer as an electrode storage solution.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eNever store a pH electrode in distilled, deionized, or reverse-osmosis water.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eUse Hanna electrode storage solution to keep the pH glass and reference junction hydrated.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eDiscard buffer after it has been used for calibration.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eCertificate, temperature-chart, packaging, and shelf-life details may vary by selected variant.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eFollow the calibration instructions provided with the specific pH meter.\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Hanna Instruments","offers":[{"title":"20 mL Sachet","offer_id":51483039039652,"sku":"HI70004G-1","price":2.29,"currency_code":"USD","in_stock":true},{"title":"500 mL Bottle","offer_id":51483039072420,"sku":"HI7004-050","price":22.5,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1298\/4199\/products\/HANNA_-GroLine-pH-4.01-Calibration-Buffer-Sachets_-20-mL-Hanna-Instruments-1670272150.jpg?v=1670272151","url":"https:\/\/www.gardensupplyguys.com\/products\/hanna-groline-ph-4-01-calibration-buffer","provider":"GARDEN SUPPLY GUYS","version":"1.0","type":"link"}