10 Best Aquarium Refractometer of September 2025

• 【Salinity Refractometer】Measure Salt Water or Salinity of Water,Monitor and Control the Concentration of Salt Water and Brine,Ideal for Aquariums and Marine Applications.
• 【Measures on 2 Scales】Specific Gravity (D 20/20) and parts per thousand and replaces your poor quality and difficult to read hydrometer.
• 【Density Measurement Range】1.0-1.070, Minimum Scale is 0.001.
• 【Concentration Measurement Range】0-100‰, Minimum Scale is 1‰.
• 【ATC】Automatic Temperature Compensation, 0-10°C.

AUTOUTLET

• Measures on 2 Scales: Aquariums refractometer features Specific Gravity (D 20/20) 1.000-1.070sg and parts per thousand 0-100PPT (1‰=1ppt=1000ppm)
• Seawater refractometer measures saltwater or salinity of water, ideal for aquarium, marine monitoring, fish-keeping,salty pools&spas and etc.
• ATC Function: salty water refractometer with automatic temperature compensation, allow you obtain accurate readings easier and faster
• Salinity Refractometer is made of aluminum body and ABS rubber light and very sturdy, comes with a hard plastic case, a mini screwdriver, a dropper
• Easy to Use: put 2-3 drops on the saltwater’s prism, towards light then to get the accurate readings through the optic eyepiece, ideal for replacement the poor quality and difficult to read hydrometer refractometer

RZ

• DESIGNED FOR - testing the concentration of saltwater, help you to monitor and control the concentration of salt water.
• WIDELY USE - Can be used for Aquariums, Marine Monitoring, Agricultural, Gardening & Educational Purposes.
• EASY , ACCURATE & AFFORDABLE - This refractometer is more accurate and easier to use than traditional hydrometers, more affordable than digital refractometers.
• DUAL SCALE -- Provides reading of 0-100PPT(parts per thousand ) and corresponding specific gravity range 1.000 to 1.070. You can get the both result at just one test.
• AUTOMATIC TEMPERTURE COMPENSATION --The build-in Automatic Temperature Compensation feature makes it get consistently accurate reading, no need to control the liquids temperature deliberately, just make sure it's at roomtemperature .

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• Upgraded Quality
• Partable Hard Storage Box
• Dual Salinity Scale
• Automatic Temperature Compensation
• Full 12 Month Replacement Warranty

Magnum Media Salinity 10ATC

• ✔ SPECIFICALLY DESIGNED REFRACTOMETER FOR SALTWATER AQUARIUM--The algorithm is made specifically for testing seawater and saltwater. This is different from a standard refractometer which is not calibrated to check salinity of aquarium water and will give an error in your readings.
• ✔ AUTOMATIC TEMPERATURE CALIBRATION --- The calibration process should be carried out with both the room and the instrument at 68° F. The refractive index of a liquid changes with temperature. Due to the automatic temperature calibration, any changes in ambient temperature from 50° F- 86° F will not affect the accuracy of the reading.
• ✔ EASY AND CLEAR READING FOR SALTWATER AQUARIUMS AND REEF TANKS--- The refractometer comes with a focus adjustment on the eyepiece, this will give you clarity of the optics and a sharp line for easy reading.
• ✔ COMES IN A SOLID CASE INCLUDES PIPETTE AND CALIBRATION TOOL --- This refractometer is not only built extremely well, but it comes with a durable hard case for easy storage of the refractometer when not in use. It also includes a calibration tool and a pipette.
• ✔ KEEP YOUR FISH AND PLANT LIFE IN OPTIMAL HEALTH--- Pure saltwater is crucial for the vitality of your marine or reef aquarium. Use this refractometer to measure the salinity of the water, the target level of salinity in a reef tank should be 35 ppt.

SunGrow

• DUAL SCALES - Saltwater Refractometer measures on specific gravity (D20/20) 1.000-1.070 and parts per thousand 0~100‰ (1‰=1ppt=1000ppm), allow you to get the result in two different units by one test
• WIDELY APPIICATION - Seawaeter Refractometer designed for Aquariums, Marine Monitoring and measures salt water or salinty of water to help you to control concentration of salt water
• EASY TO USE - Put 2-3 drops of sample solution after calibration on prism, towards light, then get the accurate readings. Hallocool aquarium refractometer is ideal for replacement salinity hydrometers or expensive digital salinity tester
• ATC FUNCTION - Salt water refraactometer can automatically compensate for changes in the ambient temperature, minimize the impact of temperature on accuracy and allow you obtain results faster and easier
• DURABLE & PORTABLE - Saline refractometer is made of aluminum and ABS rubber, anti-rust, non-staining and resistant abrasion, sturdy for long time use. Portable refractometer with plastic case easy to carry

Hallocool

• It is more accurate than a hydrometer and easy to measure. Designed for the testing the concentration of salt water and brine, perfect for use with aquarium Marine monitoring and quality control in scientific research and clinical laboratories
• Measurement range: Salinity 0 - 100 ppt, (0 - 10% salt content), SG 1.000 to 1.070 SG, Resolution: Salinity +/-1 ppt; +/-0.001 SG
• Easy to use. Place 2 drops sample on the main Prism and close the panel and hold the refractometer up to the light and look through the eyepiece.
• The refractometer's body and the retaining ring are made of brass and chrome plated. The internal optical lens with high refractive index make up the precision optical system.
• Please ignore reviews from Diver. This commentator has a suspicion of being hired. Seller opponents use unfair means to compete！

TRZ

• EASY TO USE -- The salinity refractometer is simple to operate, after calibration, just 2 drops of sample to get accurate readings through the eyepiece.
• DURABLE & PORTABLE -- The salt water tester is made of non-staining, non-corrosive and non-reactive aluminum material, superb craftsmanship, rugged design, light weight and easy to carry.
• WIDELY USE -- Can be used for Aquariums, Marine Monitoring, Agricultural, Gardening & Educational Purposes (Biology Projects)
• DUAL SCALE -- Provides reading in parts per thousand (0-100PPT) and specific gravity (1.000 to 1.070 SG) and replace the hydrometer for easier, more accurate measurement
• AUTOMATIC TEMPERTURE COMPENSATION -- With ATC function, the saltwater tester can automatically compensated according to changes in ambient temperature, accurate readings are obtained faster and easier.

HYTOMATO

• AUTOUTLET Refractometer Saltwater Aquarium has Dual scale display provides readings of one-thousandth (0-100PPT) and specific gravity (1.000 to 1.070 SG), and replace the hydrometer for easier and more accurate measurement.
• With the help of the Automatic temperature compensation(ATC function), the aquarium refractometer for saltwater can automatically compensate for changes in the ambient temperature, which can obtain accurate readings faster and more easily.
• Durable and portable, the digital salinity tester aqarium is made of non-staining, non-corrosive and non-reactive aluminum material, with superb technology, strong and durable, light weight and easy to carry.
• Widely used, can be used for fish tank,seafood water tank, salty pools & spas,aquarium and marine applications,education purpose or agricultural.
• Easy to use,marine aquarium saltwater hydrometer is easy to operate, only 2 drops of sample after calibration can get accurate reading through eyepiece.

AUTOUTLET

• It is designed for the measurement of seawater or low concentrated saltwater.
• Dual scale: 0-100‰ salinity and corresponding specific gravity 1.000-1.070
• Automatic temperature compensation function minimizes the effect of the temperature on testing result.
• Easy to Use: It's very easy to use even for new users. And no battery needed.
• Ideal for marine fishkeeping aquarium, saltwater pool, marine monitoring,lab,agricultural, gardening and educational purposes.

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