Apera Instruments SX751 pH/ORP/DO/Conductivity/TDS/Salinity/Resistivity/Portable Handheld Multiparameter Meter Kit, Silver

$236.99

Apera Instruments AI480 DO850 Optical Dissolved Oxygen Meter Kit, with 10 Ft Optical DO Probe, Hassle-Free Testing Experience

$45.5

YSI DO200 Kit EcoSense DO 200 Dissolved Oxygen Meter Kit

$169.99

GISNPA Dissolved Oxygen Meter with ATC, 0-40.00 mg/L Measurement Range, DO Meter with Electrode Filling Fluid and Anaerobic Water Calibration Powder

$82.95

UIUZMAR Dissolved Oxygen Meter Digital Dissolved Oxygen Tester with 3.6Ft DO Probe Pen Type Dissolved Oxygen Test Kit for Aquarium, Ponds, Aquaculture, Water Quality Monitoring DO Range:0.0‑20.0mg/L

$889.99

Apera Instruments AI502 EC700 Benchtop Lab Conductivity/Temperature Meter, Plastic, 1% F.S Accuracy, 0-200.0 mS/cm Range, 1-4 Points Auto Calibration

$14.15

Apera Instruments, LLC-AI314 Premium Series EC60 Waterproof Conductivity Pocket Tester Kit, ±1% F.S Accuracy, Easy Switch of EC/TDS/Salinity, Replaceable Probe

$162.87

Extech DO600 Waterproof ExStik II Dissolved Oxygen Meter

$28.92

Dissolved Oxygen Meter, Detachable Dissolved Oxygen Meter Digital Screen Display Dissolved Oxygen Sensor for Freshwater Aquaculture, Seawater Aquaculture, Swimming Pool(A)

$76.99

Apera Instruments AI311 Premium Series PH60 Waterproof pH Pocket Tester Kit, Replaceable Probe, ±0.01 pH Accuracy, Lcd display

$45.88

APERA INSTRUMENTS AI316 Premium Series PC60 5-in-1 Waterproof pH/EC (Conductivity) /TDS (ppm) /Salinity (ppt) /Temp. Multi-Parameter Pocket Tester Kit

$92.61

YSI 6050020 Pro20 Handheld Dissolved Oxygen Meter (Meter Only)

$201

Dissolved Oxygen Meter, Detachable Dissolved Oxygen Meter Digital Screen Display Dissolved Oxygen Sensor for Freshwater Aquaculture, Seawater Aquaculture, Swimming Pool(B)

$182.27

Milwaukee Instruments MW600 Standard Portable Dissolved Oxygen Meter

$889.99

YSI ProSolo Handheld Optical Dissolved Oxygen Meter Kit, ODO/T Probe with 4-m Cable

$194.19

Digital Dissolved Oxygen Detector, Dissolved Oxygen Meter Kit, DO Sensor Dissolved Oxygen Levels Tester for Aquaculture Fish Pond Sewage Treatment,Laboratories

$76.99

Digital Tester Smart Bluetooth Dissolved Oxygen Meter,Dissolved Oxygen Test Kit with Electrode Filling Fluid,Dissolved Oxygen Meter Range 0.0-30.0mg/L for Aquarium Water Test

$339.15

YINMIK Dissolved Oxygen Test Kit Accessories 1 * 50ml Zero Oxygen Calibration Reagent 2 * 30ml Electrolyte Filling Solution and 6 pcs Membrane Groups for DO Meter Tester

$331.58

RCYAGO Dissolved Oxygen Meter with Electrode Filling Fluid

$45.5

Apera Instruments Premium Series PC8500 Portable Handheld pH/Conductivity Meter Kit (AI5524)

$40.1

Apera Instruments 12.88 mS/cm (12880µS/cm) Conductivity Standard Calibration Solution, 16 oz. (AI1131)

$9.99

YSI 601026 EcoSense Kit with ODO200M Dissolved Oxygen Meter, 10M Probe and Case

$59.99

Vee Gee Scientific STX-3 Handheld Salinity Refractometer with ATC, Industrial-Grade, 0-100% Salinity Range, 1.000-1.070 Specific Gravity Range, 5-Year Warranty

$18.9

LeTkingok Dissolved Oxygen Analyzer, Dissolved Oxygen Meter 0.0-40.0 mg/L Oxygen Concentration Dector 0.0-300.0% ATC DO Meter DO9100

$76.99

YINMIK 12.88 mS/cm Calibration Solution, Conductivity Salinity Calibration Fluid for Salinity Tester, EC Meter, TDS Meter, 7 in 1 Tester Standard Calibration, 4 Bottles of 50mL

$9.99

APERA INSTRUMENTS AI209 Value Series PH20 Waterproof pH Tester Kit, ±0.1 pH Accuracy

$29.99

GISNPA PH Meter, 5 in 1 pH/TDS/EC/Salinity/Temp Meter, Waterproof Pool Salt Tester, 0.01 Resolution High Accuracy Water Tester for Drinking Water, Hydroponics, Saltwater Pool, Aquarium, Koi Fish Pond

$91.96

RCYAGO PH Meter, 5 in 1 PH/TDS/EC/Salinity/Temp Meter with ATC, 0.01 Resolution High Accuracy Water Testing for Drinking Water, Hydroponics, Seawater, Aquariums, Fish Tank and Swimming Pools

$10.79

LaMotte Water Test Education Kit, Dissolved O2

$21

CYCLOPS INSTRUMENTS Professional Salinity Premium Refractometer for Seawater, Marine Fishkeeping Aquarium, Pools, and Tanks, 0-100 PPT Salinity Tester with Automatic Temperature Compensation (ATC)

$9.19

Abuycs Salinity Refractometer for Seawater and Marine Fishkeeping Aquarium, Saltwater Tester Hydrometer, Dual Sacle 0-100ppt & 1.000-1.070 Specific Gravity with ATC Automatic Temperature Compensation

$14.99

Apera Instruments, LLC-AI481 TN400 Portable Turbidity Meter, Infrared Sensor, ISO 7027 Compliant, EPA Approved Standard Solutions for Easy Calibration, Accuracy: ±2%+Stray Light

$358

YINMIK 1413 μS/cm Calibration Solution, Conductivity Salt Standard Buffer Solution for 5 in 1 Salinity Tester, EC Meter, TDS Meter, 7 in 1 Multi-Parameter Tester Calibration, 4 Bottles of 50mL

$19.95

Apera Instruments, LLC-AI1312 Apera Instruments 201T-S pH/Temp. Electrode, 8-pin Connector, The Replacement Electrode for Apera 400/400S Series Portable Meters

$15.38

YINMIK 111.8 mS/cm Calibration Solution, Conductivity Salt Standard Buffer Solution for 5 in 1 Salinity Tester, EC Meter, TDS Meter, 7 in 1 Multi-Parameter Tester Calibration, 4 Bottles of 50mL

$18.99

GISNPA 7 in 1 pH/TDS/EC/ORP/S.G/Salinity/Temp Meter with ATC pH Tester, 0.01 Resolution High Accuracy Digital pH Meter, Water Tester for Drinking, Hydroponics, Swimming Pool and Aquarium

$29.95

YSI-605203 Pro Series Polarographic Dissolved Oxygen Sensor

$236.66

CHEMetrics Dissolved Oxygen Water Test Kit Refill

$889.99

Apera Instruments 1413 µS/cm Conductivity Standard Calibration Solution, 16 oz.

$10.9

Apera Instruments, LLC-AI3719 PC60-Z Bluetooth Multi-Parameter Smart Tester Powered by ZenTest Mobile App, Measuring pH/Conductivity/TDS/Salinity/Resistivity/Temp.

$135

Extech 780418 Internal Fill Solution for Model 407510 Dissolved Oxygen Meter

$15.99

hygger Salinity Tester, Transparent Acrylic Aquarium Hydrometer Sea Specific Gravity Test Salinity Meter for Fish Tank Pond Water Saltwater Freshwater, Accurate Automatic Hydrometer

$23.99

Auto Meter 4337 Ultra-Lite Electric Water Temperature Gauge, Silver

$18.99

Glass Aquarium Hydrometer with Built-in Marine Floating Salt Water Salinity Tester 1.000-1.060 7.87in

$10.99

Seawater Salinity Refractometer,V-Resourcing Automatic Temperature Compensation Sea Water Salinity Measurer for Aquarium, Hydrometer, 0-100ppt & 1.000-1.070 Salinity Specific Gravity

$27.99

Apera Instruments AI104G GroStar Series GS4 pH/EC/500ppm/700ppm Combo 5-in-1 Pen Tester Kit with Replaceable Double-Junction pH/EC Probe for Hydroponics Water Quality Testing, Gen II

$42.69

CHEMetrics K-7512 Dissolved Oxygen Kit, 1-12 ppm Range, 1 ppm MDL

$71.99

AUTOUTLET Salinity Refractometer Saltwater Aquarium for Seawater, Pool, Tank, Marine, Fishkeeping, 0-100PPT & 1.000-1.070 Salinity Tester with ATC Function Salinity Hydrometer Kit

$9.99

Apera Instruments pH Probe Electrode Sensor Care Maintenance Kit, Including pH 4/7/10 buffers, 3M KCL Soaking Solution, Probe Cleaning Solution, a CalPod Solution Organizer (AI1170)

$14.66

Apera Instruments AI213 Value Series TDS20 Waterproof TDS Pocket Tester kit, Accuracy: ±1% F.S, 2-Point Auto. Calibration

$8.99

Apera Instruments AI1113 pH Calibration Buffer Solution Kit (7.00, 4.00), 8 oz. Each

$7.99

Milwaukee MA841 Dissolved Oxygen Spare Membrane For use with All Dissolved O2 Meter, Pack of 5

$45.5

Dual Scale Salinity Refractometer ATC 0-100ppt (0-10%) & 1.000-1.070 Specific Gravity, Portable Meter Tester for Seawater Salt Sea Water Aquarium Brackish Reef Tank Marine

$9.99

Pinpoint® Salinity Fluid for Refractometers and Salinity Monitors

$229.99

Apera Instruments TN500 Portable White Light Turbidity Meter with Data Logger, EPA 180.1 Compliant (AI483)

$379

Pool Salt Tester & PH Meter, Hofun Digital Salinity Meter and PH Tester for Pool Saltwater and Drinking Water, 5 in 1 Salinity PH Temp EC and TDS Meter Swimming Pool Hot Tub Spas, High Accuracy

$24.99

Pool Salt Tester pH Meter ORAPXI Salinity Meter and pH Tester PPM EC Meter with LCD Screen 5 in 1- Salt pH TDS EC Meter for Saltwater Pool, Hot Tubs, Spas, Aquarium, Hydroponics System, Home Brew

$84

Milwaukee MA887 Digital Salinity Refractometer with Automatic Temperature Compensation, Yellow LED, 0 to 50 PSU, +/-2 PSU Accuracy, 1 PSU Resolution (color may vary)

$20.99

YSI-60520 Pro Series 4 Meter Cable Assembly for Dissolved Oxygen/Temperature Meter

$761.59

Auto Meter 2432 Traditional Chrome Mechanical Water Temperature Gauge

$102.99