Apera Instruments
Apera Instruments PH20 pH Tester Kit
Waterproof pocket pH tester kit with automatic calibration and a replaceable probe — the budget benchmark for pH.
pH Meters & Water Testing
pH drift is the silent yield killer — lockout looks like deficiency and sends growers chasing the wrong fix. These are the pH pens, EC/TDS meters, continuous reservoir monitors, calibration buffers and replacement probes worth owning, from pocket pens for a first tent to bench and wall-mount monitors for serious hydroponic rooms.
113 items · prices and stock live at Amazon — tap Show deal to check today's price. Full category: Meters & Testing
Bluelab
Bluelab pH Pen
The hydro-shop standard: fully waterproof, backlit display, double-junction probe and auto-off to save the battery.
Bluelab
Bluelab PENCON Conductivity (EC) Pen
Conductivity pen measuring EC, CF and ppm in 500/700 scales — fully waterproof with a backlit display.
HM Digital
HM Digital COM-80 EC/TDS Meter
Waterproof meter that reads EC, TDS and temperature with auto-calibration — a tough, affordable combo meter.
Amazon
Apera PH20 pH Pen — Waterproof, Auto Calibration
The step-up pH pen: replaceable probe, two-point auto calibration, genuinely waterproof.
Amazon
Apera EC20 Conductivity Pocket Tester
The EC twin of the PH20 — matched pair for feed mixing in under a minute.
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Milwaukee PH600 Digital pH Pen
Budget pH pen with manual calibration — the gateway meter that beats drops and strips.
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5-in-1 Water Quality Meter — pH, TDS, EC, Salinity, Temp
One pen for the whole mix: pH, EC/TDS, salinity and temperature with ATC.
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HM Digital TDS-3 Meter with Case
The classic quick TDS check for RO output and reservoir drift.
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Soil Meter 3-in-1 — Moisture, pH, Light (No Battery)
Analog probe for outdoor beds and houseplants. No batteries, instant moisture reads.
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Soil Moisture Meter XL — 12 in Probe, Battery Included
Deep probe for big pots and beds — check the bottom of the root zone, not just the crust.
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Quantum PAR Meter — Full Spectrum LED Ready
Measure actual light (PPFD) at canopy height and stop guessing about distance and dimmers.
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Digital Lux Meter — 0.1 to 200,000 Lux
Budget light meter for comparing corners and shelves. Convert to PPFD with a known factor.
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CO2 Meter Portable — NDIR with Alarm
Handheld CO2 reader for sealed rooms, greenhouses and mushroom corners.
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Govee-Style Bluetooth Thermo-Hygrometer — 2 Pack
App-logging sensors for tent and dry room. Alerts when VPD conditions drift out.
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Inkbird IBS-TH2 Bluetooth Sensor
Tiny logging sensor that lives in a jar, tent or dry box and graphs the whole cure.
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Thermometer Hygrometer with Probe — Min/Max
Wired probe reads inside the tent while the display sits outside. Min/max memory included.
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ORP Meter Pocket — for Water Sanitation Checks
Check sanitizer strength in wash water and system flushes by oxidation-reduction potential.
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Chlorine Test Strips — 100 Count
Verify dechlorination before watering living soil or filling humidifiers.
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pH Test Strips Wide Range 1-14 — 100 Count
Backup pH checks that never need calibration — keep a vial in every room.
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pH Calibration Solution Kit — 4.0, 7.0, 10.0 Packets (20 Each)
Single-use calibration packets — fresh solution is the difference between readings and guesses.
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pH Probe Storage Solution — 250 ml
Keep pen probes hydrated in storage so they stay fast and accurate.
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EC Calibration Solution 1413 — 250 ml
Standard 1413 uS solution for conductivity pens. Calibrate monthly, trust your feed.
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Refractometer for Brix — 0-32% with ATC
Measure plant sap and fruit sugar — a health and ripeness gauge for serious gardeners.
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Infrared Thermometer Gun — Laser, -58 to 1022F
Leaf-surface temperature in one trigger pull — the VPD number that actually matters.
Amazon
Leaf Thermometer Clip — IR Mini for Canopy
Clip-on spot checker for quick canopy temperature rounds.
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Waterproof Thermometer for Reservoirs — Floating
Floating reads for DWC buckets and reservoirs — roots like 65-68F, know yours.
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Light Cycle Data Logger — USB, 90 Day
Logs light and temperature — prove your dark cycle is dark and your room is steady.
Amazon
Multimeter for Growers — Voltage, Continuity, Outlet Test Kit
Chase the tripped circuit and dead outlet yourself: meter, tester and leads in one kit.
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Kill-A-Watt Style Electricity Monitor
See what each light and fan actually costs to run, per day, in dollars.
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Analog Min/Max Greenhouse Thermometer — Wall Mount
No batteries, no app — the high/low since you last reset it, at a glance.
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Bluelab Guardian Monitor — pH, EC, Temperature Wall Unit
Wall monitor that watches pH/EC/temp 24/7 with big digits — the reservoir's dashboard.
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Bluelab Truncheon EC Meter — Commercial
The indestructible EC wand every hydro shop owns — dip, read the flashing lights, done.
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Bluelab Combo Meter Plus — pH and EC in One
Two probes, one meter — the Bluelab step up from pens for daily mixing.
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Apera GroStar GS1 pH Pen — Grower Series
GroStar pH pen with a flat/soil-friendly probe option — built for nutrient mixing.
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Apera GroStar GS2 EC Pen — Grower Series
The EC half of the GroStar pair — matched design, replaceable probe.
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Hanna GroLine pH Tester HI98118 — Waterproof
Hanna's grower pH pen with a renewable junction — hydro-store counter classic.
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Hanna Soil EC Tester HI98331 — Direct Soil Probe
Stick it in the root zone — direct soil EC without slurry tests.
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Milwaukee MW802 Combo Meter — pH, EC, TDS
Bench/portable combo with separate probes — one unit for the whole mix station.
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Oakton EcoTestr pH 2+ Pocket Meter
Waterproof pocket pH with double-junction probe — lasts longer in fertilizer solutions.
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SensorPush HT1 Temperature and Humidity Sensor
Tiny pro-grade logging sensor with a serious app — alerts for tent, dry room and jars.
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Elitech Temperature Data Logger — USB, Refrigerator Grade
Cold-chain logger that graphs a whole dry/cure — plug into USB, get the PDF.
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ThermoPro TP62 Bluetooth Hygrometer Station
Bluetooth thermo-hygrometer with app history — the lounge-chair way to check the tent.
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AcuRite Greenhouse Thermometer with Humidity — Analog Dial
Big-dial analog station for the greenhouse wall — no batteries, always on.
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SpotOn Quantum PAR Sensor — Handheld
Dedicated quantum sensor with a cosine-corrected head — PPFD readings you can trust.
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Apogee MQ-500 Full-Spectrum Quantum Meter
The research-grade PAR meter — the number other meters get compared against.
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Hydrofarm PAR Meter — LED Ready Quantum Sensor
Grower-priced PAR meter tuned for LED spectrums.
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RAD-0002 CO2 Meter — Desktop NDIR with Alarm
Desktop CO2 reader for sealed rooms and offices that share air with plants.
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TIM10 Desktop CO2 Monitor — Data Logging
Logging CO2 monitor that shows the day/night breathing curve of a sealed room.
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Autopilot Desktop CO2 Monitor APCEM2
Greenhouse-brand CO2 monitor with a relay-ready design heritage.
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Luster Leaf Digital Soil pH Meter Rapitest
Digital soil pH probe from the Rapitest family — in-ground reads without mixing slurry.
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Dr.Meter S20 Soil Moisture Meter — Battery Powered
Powered soil probe with a backlit readout — clearer than the free swinging-needle meters.
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XLUX T10 Soil Moisture Meter — Long Probe Twin Pack
Two long-probe analog meters — one for the tent, one for the yard.
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Hydrometer and Test Jar Kit — for Nutrient and Brewing Checks
Floating hydrometer + jar for specific gravity — handy for teas, ferments and checks.
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Sugar Brix Refractometer 0-90% — Fruit and Sap
Wide-range refractometer for fruit ripeness and plant sap checks.
Amazon
Outlet Power Monitor with Backlight — Voltage and Cost
Plug-through monitor that shows watts, volts and running cost per device.
Amazon
Infrared Thermometer Mini — Pocket Size
Pocket IR gun for leaf and surface temps on scouting rounds.
Amazon
Waterproof Digital Thermometer 2-Pack — Aquarium and Reservoir
Stick-on/probe thermometers for reservoirs and tanks — a matched pair.
Amazon
Apera PH60 Premium pH Pocket Tester Kit — ±0.01, Replaceable Probe
Apera's premium pocket tester reads to ±0.01 pH with a 3-in-1 probe you can swap when it ages out. Ships in a hard case with calibration buffers and storage solution, so it arrives ready to work.
Amazon
Apera PC60 5-in-1 Pocket Tester — pH, EC, TDS, Salinity, Temp
One pen covers the whole reservoir checklist: pH, conductivity, TDS, salinity and temperature on a backlit dual display. Waterproof body, automatic temperature compensation and a replaceable multi-parameter probe.
Amazon
Apera AI316 Premium 3-in-1 Tester Kit — pH, EC, TDS in Hard Case
A kit-format combo tester that measures pH, EC and TDS with one probe and stores everything — buffers included — in a fitted case. A good single buy for growers tired of juggling separate pens.
Amazon
Apera PH700 Benchtop pH Meter — Lab Bench Accuracy ±0.01
A bench meter for the mixing station: stable ±0.01 readings, a probe arm that holds the electrode in the sample, and room for 500 stored readings. Better than a pen when you mix big reservoirs daily.
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Apera SX610 Pen pH Meter — Slim Waterproof Tester
A slim, fully waterproof pH pen built for quick spot checks in buckets, reservoirs and runoff trays. One-touch calibration and a pocket clip make it the grab-and-go option.
Amazon
Bluelab Soil pH Pen — Spear Tip for Media and Root Zone
Bluelab's soil pen pushes a spear-tip probe straight into coco, soil or rockwool so you measure the root zone itself, not just the feed. Also reads liquid pH, with a dibber for making consistent probe holes.
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Bluelab Leap pH Probe — Direct Media Probe for Meters and Monitors
A reinforced spear probe that plugs into Bluelab meters and monitors and reads pH directly in the substrate. Built for repeated poking into media without the fragile glass tip of a standard electrode.
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Bluelab OnePen — Bluetooth pH, EC and Temp Pen with App
Bluelab's connected pen measures pH, EC and temperature and logs every reading to the Edenic app over Bluetooth. Bright dual-line display still works standalone when the phone is in your pocket.
Amazon
Bluelab Replacement pH Probe — BNC, for Combo Meter and Guardian
The genuine replacement electrode for Bluelab Combo Meters and Guardian monitors, with a standard BNC connector and 2 m cable. Double-junction design holds up better in nutrient solution than budget glass.
Amazon
Bluelab Probe Care Kit — pH and EC Cleaning and Calibration
Everything Bluelab wants you using on their probes in one box: pH 4 and 7 buffers, EC 2.77 standard, storage solution, cleaning solution and scrub tools. Regular care is the difference between a 6-month probe and a 2-year probe.
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Bluelab EC 2.77 Calibration Solution — 250 ml Bottle
The 2.77 mS/cm conductivity standard Bluelab truncheons and EC pens are calibrated against. Bottled solution stays accurate longer than opened single-use packets in a warm grow room.
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Milwaukee MW102 PRO pH Meter — Portable, ±0.02, Separate Probe
A workhorse handheld with the probe on a cable, so the electronics stay dry while the electrode sits in the reservoir. Reads pH and temperature to ±0.02 with two-point calibration.
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Milwaukee MW100 PRO pH Meter — 0.01 Resolution Handheld
Milwaukee's simpler PRO handheld: fast 0.01-resolution pH readings, manual two-point calibration and a replaceable probe. A step up from disposable pens without benchtop money.
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Milwaukee PH55 PRO Waterproof pH Tester — Replaceable Electrode
Fully waterproof pocket tester with a double-junction electrode you can replace instead of binning the whole meter. Large digits, automatic temperature compensation and push-button calibration.
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Milwaukee EC60 PRO 3-in-1 Tester — EC, TDS and Temp, Waterproof
Waterproof combo pen covering EC, TDS and temperature with a replaceable graphite sensor that shrugs off nutrient salts. Graphite electrodes do not corrode the way metal pins do in fertilizer solution.
Amazon
Milwaukee MC120 PRO pH Monitor — Continuous Readout with Alarm
Mount it by the reservoir and watch pH around the clock: continuous display, a settable alarm range, and a probe that lives in the tank. Catches overnight drift that a twice-a-day pen check misses.
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Milwaukee MC122 PRO pH Controller — Switches a Dosing Pump
A monitor that acts: when reservoir pH climbs past your setpoint it powers a dosing pump or CO2 regulator through its switched outlet, then stops at target. The entry point to automated pH control.
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Milwaukee MW600 PRO Dissolved Oxygen Meter — 0.0 to 19.9 mg/L
Measures dissolved oxygen in reservoirs and DWC buckets, where roots suffocate quietly when air pumps fail or water warms up. Galvanic probe needs no warm-up polarization time.
Amazon
Milwaukee MW500 PRO ORP Meter — -999 to +1000 mV
A bench-style ORP meter for checking sanitizer strength in irrigation lines and reservoir sterilization routines. Far more repeatable than the pocket ORP pens when you are dialing in peroxide or hypochlorous doses.
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Milwaukee pH 7.01 Buffer Solution — 230 ml Bottle (MA9007)
The single-point buffer most growers burn through fastest, in a proper 230 ml lab bottle instead of sachets. Pair it with a 4.01 bottle for a full two-point calibration.
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Hanna HI98131 GroLine Combo Tester — pH, EC, TDS, Temp Waterproof
Hanna's grower combo pen reads pH, EC, TDS and temperature, and the pH junction pulls out to clear clogs — the number-one killer of hydroponic electrodes. Cal-Check warns you when the probe needs attention.
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Hanna HI9814 GroLine Portable Meter — pH, EC, TDS with Quick-Connect Probe
A handheld meter on a quick-connect DIN probe that measures pH, EC and TDS in one dip. Rugged, splash-proof housing made for greenhouse benches and mixing rooms.
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Hanna HI981420 GroLine Monitor — Continuous pH, EC and Temp Wall Unit
A continuous wall monitor with a big green LED readout you can read across the room, plus high/low alarms for pH and EC. The probe stays in the reservoir so drift never sneaks up between hand checks.
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Hanna HI98108 pHep+ Pocket Tester — 0.01 Resolution, Renewal Junction
The updated pHep pocket tester with 0.01 resolution and a renewable cloth junction — pull out a fresh section when readings slow down instead of replacing the meter. Waterproof and pocket-cheap to run.
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Hanna HI98301 DiST 1 TDS Pocket Tester — 0 to 2000 ppm
A simple, tough TDS pen for checking source water and mixed nutrients, with an exposed temperature sensor for honest automatic compensation. Graphite sensor resists the corrosion that kills pin-style testers.
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Hanna HI7061 Electrode Cleaning Solution — General Purpose, 230 ml
The soak that rescues slow, drifting pH electrodes: 15-20 minutes strips the nutrient film and salt crust that calibration alone cannot fix. Cheap insurance before you write off a probe as dead.
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HM Digital PH-200 Waterproof pH Meter — ±0.02, Replaceable Sensor
A waterproof pH meter with a replaceable sensor, on-screen calibration and simultaneous temperature readout. Holds calibration well and survives being dropped in the reservoir better than most pens.
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HM Digital PH-80 pH HydroTester — Push-Button Calibration
HM Digital's budget pH pen done right: waterproof, one-touch calibration at pH 7 with included buffer, and a low-battery indicator so it never dies silently mid-mix.
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HM Digital COM-100 Waterproof EC, TDS and Temp Meter — Professional
The sealed, professional sibling of the COM-80: waterproof housing, three conductivity ranges, replaceable sensor and both KCl and NaCl TDS modes. Built for daily commercial use.
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HM Digital TDS-EZ TDS Tester — Simple Source-Water Pen
A no-frills TDS pen for the two checks that matter most: incoming tap or RO water, and finished nutrient mix. Auto-off, hold function and a price that makes it a fine backup meter.
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HM Digital DM-1 Inline Dual TDS Monitor — In and Out Readings for RO
Plumbs into your RO unit and shows TDS before and after the membrane at once, so you know the day the membrane gives up instead of guessing from plant symptoms. Battery powered, push-to-read.
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HM Digital TDS Calibration Solution — 1000 ppm NaCl, 342 ppm Option
Certified NaCl standards for checking TDS and EC pens against a known value. If your pen reads the standard wrong, every reservoir you mix is wrong by the same amount.
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Dr.Meter PH100 pH Meter Kit — 0.01 Resolution with Buffer Packets
A full starter kit: 0.01-resolution meter, buffer packets for three-point calibration, and a carry case. Automatic temperature compensation keeps readings honest between cold well water and warm reservoirs.
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YINMIK Digital pH Meter — Hydroponics Tester, 0.01 Accuracy, ATC
A hydroponics-focused pH pen with three-point automatic calibration and a backlit screen you can read in a dim tent. Recognizes buffer solutions automatically so calibration takes under a minute.
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YINMIK EC and TDS Meter — 3-in-1 with Temperature, Hold Function
YINMIK's companion conductivity pen covers EC, TDS and temperature with a hold button for catching the reading in awkward reservoir corners. A sensible matched pair with their pH pen.
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Jellas Pocket pH Meter — Digital Tester with Buffer Packets
One of Amazon's long-running budget pH pens: 0.01 display resolution, two-point calibration and buffer packets in the box. A realistic first meter or a glovebox spare for the main one.
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Extech PH100 ExStik Waterproof pH Meter — Flat-Surface Electrode
The ExStik's flat electrode reads pH on surfaces and in tiny samples where bulb probes cannot go — runoff on a tray, a soaked cube, a drop of feed. Waterproof, with a memory that stores 15 readings.
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Extech EC400 ExStik II — EC, TDS, Salinity and Temp in One Pen
A four-parameter stick meter covering conductivity, TDS, salinity and temperature with a self-cleaning sensor cap. Autoranging keeps it simple for growers who just want the number.
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Oakton pHTestr 30 Waterproof Pocket Tester — Double Junction, ±0.01
Oakton's premium pocket tester uses a double-junction sensor that tolerates nutrient contamination longer between cleanings, with true ±0.01 accuracy. Floats if dropped in the tank.
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Oakton EcoTestr CTS Pocket Tester — EC, TDS and Salinity
The conductivity member of Oakton's EcoTestr family: pin-style sensor, waterproof body and push-button calibration. Covers EC for feeding charts and TDS for source-water checks.
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LaMotte Garden Soil Test Kit — pH and NPK Color-Chart Tests
LaMotte's classic reagent kit tests soil pH, nitrogen, phosphorus and potassium with color comparators and enough supplies for repeated tests. The lab brand schools and extension offices have used for decades.
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MySoil Test Kit — Mail-In Laboratory Soil Analysis
Scoop soil, mail the prepaid envelope, and get a real laboratory report with pH, macro and micronutrients plus amendment recommendations by weight. The definitive answer when pen-and-probe soil guesses disagree.
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General Hydroponics pH Test Kit — Liquid Drops, Vial and Color Chart
The old-school drop test: fill the vial, add drops, match the color. No batteries, no calibration, nothing to drift — every grower should own one as a sanity check on their electronic meter.
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API Freshwater Master Test Kit — Liquid pH, Ammonia, Nitrite, Nitrate
Liquid reagent tests for growers on well, rain or aquarium-sourced water: high and low range pH plus ammonia, nitrite and nitrate, hundreds of tests per box. Far more accurate than dip strips for source water.
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Varify 17-in-1 Drinking Water Test Strips — 100 Count plus Bacteria Tests
Seventeen checks on one strip — pH, hardness, chlorine, lead, iron, copper, nitrates and more — plus two bacteria vials in the box. The fast way to profile a new water source before you build a feeding program on it.
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Milwaukee MA871 Digital Brix Refractometer — 0 to 85 Percent
A digital refractometer that reads Brix at the press of a button and removes the squint-at-the-line guesswork of optical models. Sap and plant-juice Brix is a quick plant-health and flavor indicator at harvest.
Amazon
Salinity Refractometer — 0 to 100 ppt, Dual Scale Specific Gravity
An optical refractometer scaled for salinity and specific gravity instead of sugar — the right tool for checking brackish mixes, salt-based additives and aquarium water used in reef-style mineral blends. ATC keeps temperature out of the reading.
Amazon
REOTEMP Long-Stem Soil Moisture Meter — 24 in Analog Probe
A commercial-grade analog moisture meter on a 24-inch stem that reads moisture deep in beds, big pots and outdoor plots where surface checks lie. No batteries — the probe generates the signal itself.
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ECOWITT WH51 Wireless Soil Moisture Sensor — App Readings with Gateway
A probe that reports soil moisture to your phone through an ECOWITT gateway, so you can watch dry-down curves between waterings instead of poking the soil. Runs about a year on one AA battery.
Amazon
Bluelab Pulse Multimedia EC and Moisture Meter — Root-Zone EC in Seconds
Bluelab's handheld Pulse reads pore EC, moisture content and temperature directly in the substrate with one press against the media. It measures what roots actually sit in — the number feed charts cannot tell you.
Amazon
Graduated Cylinder Set — Borosilicate Glass, 10 to 250 ml, 5 Sizes
Proper glass cylinders for measuring concentrates accurately — thin liquids read to the line instead of the sloppy guesswork of a kitchen jug. Five sizes cover everything from additives by the milliliter to full mixes.
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Borosilicate Beaker Set — 5 Piece, 50 to 1000 ml with Graduations
Heat-safe glass beakers for warming, dissolving and pre-mixing nutrients before they hit the reservoir. Graduated markings, pouring spouts and a size for every step of the mixing bench.
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Plastic Transfer Pipettes — 3 ml Graduated, 100 Pack
Disposable graduated pipettes for pulling samples, dosing drops and moving calibration liquids without contaminating the bottles. At 100 to a bag they are the cheapest lab habit a grower can pick up.
Amazon
Replacement pH Electrode Probe — BNC Connector with 3 ft Cable
A universal glass pH electrode with a standard BNC plug that fits most monitors, controllers and bench meters. The standard rescue when a continuous monitor starts drifting and a cleaning soak does not bring it back.
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Apera Replacement Probe for PH60 Series — 3-in-1 pH and Temp Electrode
The genuine Apera replacement sensor for PH60 testers: unscrew the tired probe, fit the new one, recalibrate and the meter reads like new. Keeping a spare on the shelf means zero downtime mid-cycle.