Editor's Choice - Our Favorite Digital Aquarium Hydrometers

1. GXSTWU Reptile Hygrometer Thermometer LCD Display Digital Reptile Tank Hygrometer Thermometer with H...

User Ratings: 71 5

GXSTWU HY-2 First Impressions

"Couldn't be happier."

I compared the readings using this hygrometer and the calibrated refractometer. But with alittle persistance I am able to read it. Not sure how accurate it is, but it's a good reference point. There are conversion charts and tables online. I will get one later but for now this will do, since im just starting. So once your instant ocean shows a measurement. Find a good light source to make reading easier.

• GXSTWU Reptile Hygrometer Thermometer LCD Display Digital Reptile Tank Hygrometer Thermometer with Hook Temperature Humidity Meter Gauge for Reptile Tanks, Terrariums, Vivarium
• 100% Brand New and High-Quality Reptile Tank Thermometer Hygrometer: Precise supervision of the temperature and air humidity in terrariums, vivariums and reptile tanks.
• Stylish Design: Stylish looking digital vivarum thermometer with hook and loop for easy to install to any reptile tanks or terrariums. Comes with a battery so you can use the thermometer immediately.
• Fantastic Value: This accurate reptile thermometer and hygrometer allows you to monitor the temperature and humidity in the reptile tanks at all times to makesure your beloved reptiles are in perfect health.
• Fahrenheit Celsius Convertible: Temperature can be display in Fahrenheit or Celsius by press the C/F hole on the back of the item with a paper clip.
• Quality Guaranteed: Our carefully sourced range of thermometer hygrometers are manufactured to the highest of standards our customers expect. And provide 365 days warranty, in case of any quality problems, please feel free to contact us by email, we will give you a satisfactory solution.
• Manufacture: Cangda Electronics Co., Ltd.
• Product Dimensions: 2.09 x 0.67 x 1.3 inches; 0.92 Ounces
• Batteries: 1 LR44 batteries required. (included)

• Editor's Impressions Of The GXSTWU HY-2
• Accuracy [star rating='4.7']
• Quality [star rating='4.7']
• Value For Money [star rating='3.5']
• Affordability [star rating='4.8']

Peoples Choice - Other Highly Rated Digital Aquarium Hydrometers

2. Eyourlife Salinity Refractomer Aquarium Optical Optics Refractometer with Auto Temperature Compensat...

User Ratings: 64 8

Eyourlife First Impressions

"So easy to use."

Great tool if you have a salt-water fish tank or a decorative pond. Ultimately, the measurement was exactly the same as our old tester. I have purchased before will buy again! Great product I used for beer making and my saltwater aquarium. I would suggest purchasing the salt calibration solution. I tried it over and over and no bubbles! Very quick to calibrate and to use.

• Eyourlife Salinity Refractomer Aquarium Optical Optics Refractometer with Auto Temperature Compensation ATC Digital Dual Scale Salinity Meter Hydrometer Specific Gravity for Saltwater Seawater Marine
• SALINITY REFRACTOMETER for measuring the salinity of salt water quickly and accurately, ideal for agriculture, industry and research application, such as Mariculture, Fish Culture, Aquarium, Marine Survey, Water Quality Monitoring, Salt Production, Manufacture of Normal Saline, Salinity Measurement in Food Processing etc. It can also be used for medical institutions and university research.
• DUAL SCALES: The Refractometer is a equipment to measure the liquid concentration(the concentration of salt) by using the light, working basis on that the liquid with different concentrations have different light refractive index. The Measures on 2 scales: Specific Gravity (0.001, Range: 1.000 - 1.070, D 20/20,) and Parts Per Thousand (1‰, Range: 0-100‰).
• ATC FUNCTION: Automatic Temperature Compensation during 10-30℃, eliminating data errors caused by temperature changes and guaranteeing a consistent accurate result.
• WITH DURABLE STORAGE CASING: With a sturdy and light weighted case, it is very convenient to storage and carry. The body is made of stainless steel and is very durable, the eyepiece is in high quality for better viewing, adopting optical glass lens rather than plastic lens for accurate measurement.
• PACKAGING: 1 x Salinity Refractometer, 1 Pipette, 1 x Instruction manual, 1 x Mini screwdriver, with a durable storage case.
• 1 x Salinity Refractometer
• 1 x Pipette
• 1 x Instruction Manual
• Manufacture: Eyourlife
• Product Dimensions: 7.91 x 2.99 x 2.2 inches; 5.6 Ounces

• Editor's Impressions Of The Eyourlife
• Accuracy [star rating='3.9']
• Quality [star rating='3.4']
• Value For Money [star rating='4.9']
• Affordability [star rating='5']

3. Aquarium Refractometer, Seawater Salinity Meter Aquarium Optics Refractometer Temperature ATC Digita...

Hongzer First Impressions

"Easy to use."

Functions just as it is supposed to. It is essential to get some specialized aquarium calibration fluid for 1. It is easy to read and perform the procedure in seconds. It did not need adjusting to calibrate, though I tried to just to see how it worked. Once I figured that out, it works great. Be sure to buy the calibration solution and test this before use! So once your instant ocean shows a measurement.

• Aquarium Refractometer, Seawater Salinity Meter Aquarium Optics Refractometer Temperature ATC Digital 0-10%
• 0 to 10% salinity, 0.01% scale.
• Durable aluminum body, durable and can use for a long time.
• Adjust the focus by twisting the handle.
• Compact design with rubber handle.
• Soft and flexible eyepiece for added comfort. Instant and reliable aqueous solution measurement.
• Manufacture: Hongzer
• Item Weight: 8.4 ounces
• Product Dimensions: 6.69 x 1.57 x 1.57 inches

• Editor's Impressions Of The Hongzer
• Accuracy [star rating='5']
• Quality [star rating='5']
• Value For Money [star rating='5']
• Affordability [star rating='5']

4. Digital Salinity Meter, SA287 Portable Digital Salinity Meter High Precision Salinity Temperature Pe...

Jadpes First Impressions

"Works great for reefing!"

At first, I was getting bubbles sticking to the rotating arrow. Perfrct for someone learning or anyone for that matter. Works great,& comes in a storage box. Then I made a mark on it to set the salinity of my fish tank. Bubbles can greatly affect the reading. I tried it over and over and no bubbles! I think those reviews just didn't know how to use it properly.

• Digital Salinity Meter, SA287 Portable Digital Salinity Meter High Precision Salinity Temperature Pen Type Tester for Saltwater, Swimming Pool, Aquaculture, Aquarium
• WATERPROOF SALINITY METER:It displays the salinity value precisely, compact size and light weight, easy and portable to carry, convenient to use.This instrument can not only detect the salt content of edible salt, salt water pool and koi fish pond, but also the salinity of seawater, marine, salt water fish tank salt level testing.
• SALINITY TESTER:Digital Salinity Tester for Salt Water.The pen type salinity meter is a precision instrument for testing the salinity value of a solution.Quick and reliable manner for most regular water solutions' testing.
• WIDE APPLICATIONS:Suitable for saltwater, swimming pool, aquaculture, aquarium (seawater) and pond, food processing and health care products industry. Saltwater Tester for Seawater, Aquariums, Marine Monitoring.
• BACKLIT DESIGN:It adopts large screen LCD, PPT standard unit display, power display, power data protection function, automatic temperature compensation, dustproof and waterproof functions.
• APPLICATION:Its full-featured performance, easy operation and replaceable electrodes make it the best choice for rapid, accurate salinity testing in laboratories, sites and schools.
• Manufacture: Jadpes
• Product Dimensions: 0.39 x 0.39 x 0.39 inches; 5.29 Ounces

• Editor's Impressions Of The Jadpes
• Accuracy [star rating='3.3']
• Quality [star rating='2.9']
• Value For Money [star rating='3']
• Affordability [star rating='2.7']

Honorable Mentions - More Top Selling Digital Aquarium Hydrometers

5. Digital Salinity Tester for Salt Water - Aquarium Salinity Meter with ATC, IP67 Waterproof, 0-200 PP...

CIZTADA First Impressions

"Works great for reefing!"

Functions just as it is supposed to. Looks to provide very accurate readings. Waterproof if you accidentally drop it in the pool. Does just as good of a job of any meter you would buy at the store! I have a 2000+ gallon pond and I just put salt in it last month. Comes with a nice carrying case for easy and secure transportation. Good quality and simple to use refractometer.

• Digital Salinity Tester for Salt Water - Aquarium Salinity Meter with ATC, IP67 Waterproof, 0-200 PPT Large Range Multi-Parameter Tester for Seawater, Fish Tank, Hydroponics
• [Large Salinity Range] Ciztada salinity tester has 2 measurement modes, scale range: 0~9999 ppm/10.0~200 ppt and 0.00-25.00%, which is 2 times than the salinity refractometer
• [Automatic Temperature Compensation] Ciztada salinity tester is equipped with ATC part inside, during normal temperature, once calibrated, the temperature change would never affect the accurate of your measuring result. This makes it more convenient to use in different temperature
• [Easy Reading with LCD Backlight] There is no need to worry about seeing the displayed value if the light is insufficient. Ciztada salinity meter features a green backlit LCD to help you see the measurement results clearly in any situation
• [Multifunctional Salinity tester]: The Ciztada multi-parameter Tester can test Salinity, TDS, EC and Temperature in an accurate, quick and reliable manner for most regular water solutions' testing. Support One-tap switch from salinity to TDS/EC
• [Wide Applications]: Measures saltwater or salinity of water, ideal for aquarium, marine monitoring, salty pools & spas, koi fish pond, hydroponics and etc
• Manufacture: CIZTADA
• Batteries: 3 LR44 batteries required. (included)

• Editor's Impressions Of The CIZTADA
• Accuracy [star rating='5']
• Quality [star rating='4.6']
• Value For Money [star rating='4.6']
• Affordability [star rating='5']

6. Bubble Magus Digital Color Screen Salinity Meter

Bubble Magus First Impressions

"Good value."

YOU WILL NOT get an accurate reading if there are bubbles on the needle. Every time I leave to do something I come back and it's at the bottom of my tank. On the shaft of the refractometer, there's a little, rubber-covered nub. However, the numbers are soooo small it is sometimes hard to read. Just rinse with warm water afterwards. I use this for my 10g brackish and it works ok. Bought this as a back up refractometer.

• Bubble Magus Digital Color Screen Salinity Meter
• Manufacture: Bubble Magus

• Editor's Impressions Of The Bubble Magus
• Accuracy [star rating='4.8']
• Quality [star rating='5']
• Value For Money [star rating='4.1']
• Affordability [star rating='4.7']

Here Are Some Other Related Aquarium Hydrometers

7. Abuycs Salinity Refractometer for Seawater and Marine Fishkeeping Aquarium, Saltwater Tester Hydrome...

User Ratings: 86

Abuycs First Impressions

"This tool is AMAZING!"

I have gone two years in this hobby with a hydrometer. I will get one later but for now this will do, since im just starting. The unit is really easy to calibrate and used. I use this for my 10g brackish and it works ok. My meter came already calibrated to 0. The instant ocean hydrometer will always be right. Works well on my Saltwater Aquarium.

• 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
• ✅DUAL SCALE MEASURES SALT PERCENT AND SG:Specific gravity,range: 1.000-1.070 g/cm3, resolution: 0.001 g/cm3.Salt percent, range: 0-100 ppt ( or say parts per thousand), resolution: 1 ppt.It is designed for the measurement of seawater (marine aquaria) or very low concentrated salt solutions.
• ✅ ENDLESS APPLICATION AND EASY TO USE,:Ideal for testing and monitoring aquariums,fish tank, saltwater pool,seawater.Just need 2-3 drops of solution, you can get accurate readings. No batteries needed.
• ✅ATC TECHNOLOGY:Handheld Salinity Refractometerr with Automatic Temperature Compensation(ATC),no more worry about the temperature change will influence the reading accuracy.the fish keeping refractometer will account for changes in ambient temperature and automatically compensate accordingly to provides accurate and repeatable measurements.
• ✅AIRCRAFT ALUMIUM BODY MATERIAL:The aquarium refractometer is made of non-staining, non-corrosive and non-reactive aluminum which is lightweight to carry,anti-scratch and durable.
• ✅WIDE APPLICATION: It is for measuring the salinity of salt water quickly and accurately, ideal for agriculture, industry and research application, such as mariculture, fish culture, aquarium, marine survey, water quality monitoring, salt production, manufacture of normal saline, salinity measurement in food processing etc. Can also be used for medical institutions, university research and so on.
• Manufacture: Rockgood ltd.

• Editor's Impressions Of The Abuycs
• Accuracy [star rating='4']
• Quality [star rating='5']
• Value For Money [star rating='5']
• Affordability [star rating='5']

8. UEETEK Heavy Duty Submersible Pump for Aquarium,Powerhead Fountain Water Hydroponic Pump with US-plu...

User Ratings: 51 49

UEETEK First Impressions

"Other then that."

Just give me one simple, accurate reading to go by, and I'm happy. Make sure to knock out the bubbles on the white dial by hitting it with your knuckle. Comes with a nice carrying case for easy and secure transportation. Does just as good of a job of any meter you would buy at the store! This is perfect to keep a check on the salt level in your tank. Small problem with bubbles on the needle but other than that no issues. Very easy, turn screw very slowly to calibrate.

• UEETEK Heavy Duty Submersible Pump for Aquarium,Powerhead Fountain Water Hydroponic Pump with US-plug for Fish Tank,2.3 x 1.7 x 2.0 inch (L x W x H)
• This submersible pump is designed for reliability and ultra-quiet operation.
• Small size, high efficiency, low consumption, low noise.
• Suction cups to fit vertical or horizontal mounting.
• Suitable for use in hydroponic systems, ponds, fresh and saltwater aquariums, fountains and filter systems.
• Note: The item is with US plug adapter：NLY for 110V, NOT for 220V. Please confirm the voltage of your area before placing an order.
• Manufacture: UEETEK
• Product Dimensions: 2.28 x 1.65 x 1.97 inches; 7.41 Ounces

• Editor's Impressions Of The UEETEK
• Accuracy [star rating='2.3']
• Quality [star rating='3.5']
• Value For Money [star rating='4']
• Affordability [star rating='3.1']

9. Rhino Clinical Pet (Dog & Cat) Refractometer HR305 (ATC), Urine Specific Test

RHINO TECHNOLOGY First Impressions

"Easy to use."

If you let it sit in the tank overnight, it definitely gives an accurate reading. It's perfectly accurate based on the known calibration fluid. Functions just as it is supposed to. Plenty of info on YouTube and the web if you don't know how. I don't want to deal with temperature correction or. I've tried several different refractometers now and they are mostly the same. YOU WILL NOT get an accurate reading if there are bubbles on the needle.

• Rhino Clinical Pet (Dog & Cat) Refractometer HR305 (ATC), Urine Specific Test
• The Rhino Pet refractometer HR305 can be used to read Specific Gravity of Dog Urine, Specific Gravity of Cat Urine,and Serum or Plasma Protein.
• We provide 2 years quality warranty and customize services for the Pet refractometer.
• The surface of the refractometer is sprayed with Teflon,It has the characteristics of wear resistance, corrosion resistance, anti-static and anti-adhesion.
• The Rhino Pet hand-held Refractometer come with portable holster, water bottle, calibration mini-screwdriver, english instruction manual, cleaning cloth, plastic pipette and case.
• Rhino Pet refractometer with Automatic Temperature Compensation ( 50°F~86°F / 10°C~30°C ).
• Manufacture: RHINO TECHNOLOGY

• Editor's Impressions Of The RHINO TECHNOLOGY
• Accuracy [star rating='5']
• Quality [star rating='4.4']
• Value For Money [star rating='5']
• Affordability [star rating='5']

10. Aquarium Salinity Refractometer for Brackish/Marine/Reef Tank Testing,Hobein Dual Scale Automatic Te...

User Ratings: 68 6

Hobein First Impressions

"Calibrate it, use it."

And always make sure there is no bubbles on the measuring unit. When I compared it to what my local pet store was reading my water at it was dead on. Be sure to adjust the focus by turning the eye focal when you first receive. Plus it is super easy to use and clean. Be sure to adjust the focus by turning the eye focal when you first receive. Was calibrated and worked perfect right out of the box. It is easy to read and perform the procedure in seconds.

• Aquarium Salinity Refractometer for Brackish/Marine/Reef Tank Testing,Hobein Dual Scale Automatic Temperature Compensation 0-100ppt & 1.000-1.070 Specific Gravity with ATC
• ❤DUAL SCALE: Measuring Ranges: 0-100 ppt of Salinity and 1.000 to 1.070 Specific Gravity (0-10%)the reading resolution is 0.1 %. Salinity Accuracy: +/-0.1%
• ❤APPLICATIONS: Aquariums, Marine Monitoring, Agricultural, Gardening & Educational Purposes (Biology Projects)
• ❤EASY TO USE:Automatic Temperature Compensation (ATC),Just need 2-3 drops of solution,you will be able to read accurately the result
• ❤PORTABLE AND DURABLE: Made with non-staining, non-corrosive and non-reactive aluminum material, light-weighted and portable, safe and durable
• ❤PACKAGE INCLUDES: 1 Refractometer, 1 Carrying Case, 1 Calibrating Screw Driver, 2 Pippets, 1 Cleaning Clothe, 1 Instruction Manual
• Manufacture: Hobein

• Editor's Impressions Of The Hobein
• Accuracy [star rating='5']
• Quality [star rating='4.9']
• Value For Money [star rating='3.9']
• Affordability [star rating='4.7']