Editor's Choice - Our Favorite Sera Aquarium Hydrometers

1. Sera Marin Hydrometer

User Ratings: 51 7

Sera 8910 First Impressions

"Easy to calibrate."

He is too cute not to want to take care of properly. My only criticism would be that it's a little too dark. I have to recalibrate it ever use though which worries me sometimes. Too that makes it appear too cheap. I have tried others before but this has given me accurate and stable results. The water was at what I expected it should be. This requires repeatedly tapping the arm with a pencil.

  • Sera Marin Hydrometer
  • Country Of Origin : China
  • The Package Height Of The Product Is 7.48 Inches
  • The Package Length Of The Product Is 2 Inches
  • The Package Width Of The Product Is 1.38 Inches
  • Manufacture: Sera North America, Inc.
  • Product Dimensions: 1.18 x 1.38 x 7.48 inches; 1.28 Ounces
  • Editor's Impressions Of The Sera 8910
  • Accuracy [star rating='5']
  • Quality [star rating='4.6']
  • Value For Money [star rating='4.1']
  • Affordability [star rating='3.8']

Sera 8910 Final Thoughts

"I highly recommend!"

The refractor was off out off the box. Pretty darn accurate for the price. It's perfectly accurate based on the known calibration fluid. Now that it's calibrated I love it! 026 and the tank isn't, new animals will go into shock. Bought this one to check my old one, this one checked right on the dot at 1. All very easy and I feel as though I am getting an accurate salinity reading.

Overall Score
4.0

[star rating="4"]
(58 Points)

2. Premium Salinity Refractometer with Automatic Temperature Compensation for Saltwater, Aquarium, Mari...

User Ratings: 75 9

ONE250 First Impressions

"Arrived quickly."

I HIGHLY recommend this to Aquarists! Find a good light source to make reading easier. But with alittle persistance I am able to read it. My corals will be much happier now. I would recommend this product to anyone that has a marine aquarium. It's perfectly accurate based on the known calibration fluid. When I compared it to what my local pet store was reading my water at it was dead on.

  • Premium Salinity Refractometer with Automatic Temperature Compensation for Saltwater, Aquarium, Marine Reef Tank Testing - Dual Scale (0-100ppt & 1.000 to 1.070 S.G.)
  • ✔ Hand-held analog salt meter; Light-weight, portable, includes protective carrying case
  • ✔ Measures concentration of salt and dissolved solids in aqueous solution
  • ✔ Provides reading in parts per thousand (0-100PPT) and specific gravity (1.000 to 1.070 SG)
  • ✔ Ideal for on-site measurements in processing and storage areas, or in the field
  • ✔ Determine salinity during preparation of pickles, seafood products, frozen vegetables and fruits
  • Manufacture: ONE250
  • Product Dimensions: 8 x 3 x 2 inches; 9.14 Ounces
  • Editor's Impressions Of The ONE250
  • Accuracy [star rating='4']
  • Quality [star rating='5']
  • Value For Money [star rating='5']
  • Affordability [star rating='4.2']

ONE250 Final Thoughts

"This tool does that."

Compare it with the refractometer and adjust the refractometer so that it matches. On the shaft of the refractometer, there's a little, rubber-covered nub. I bought this refractometer as a more accurate option for salinity than a hydrometer. Be sure to buy the calibration solution and test this before use! Bought this as a back up refractometer. 026 with the new Aquatic Experts fluid. I felt it wasn't accurate which was verified by my LFS.

Overall Score
4.5

[star rating="4.5"]
(18 Points)

3. TOPINCN Square Saltwater Hydrometer Salt Water Salinity Meter Accurate Automatic Hydrometer Salt Wat...

TOPINCN First Impressions

"Super easy to use."

Then I made a mark on it to set the salinity of my fish tank. This device is a godsend and so much easier and cleaner to use. 027, I'm so glad I bought this one and it came spot on. I would recommend you to purchase this and skip the other ones. This refractor should last a good number of years. Find a good light source to make reading easier. Just rinse with warm water afterwards.

  • TOPINCN Square Saltwater Hydrometer Salt Water Salinity Meter Accurate Automatic Hydrometer Salt Water Salinity Meter for Fish Tank
  • Accurate, durable, and easy to read sea water hydrometer
  • This product is designed with an automatic level function, can automatically identify the level to avoid errors
  • Very accurate measurement readings, please rest assured to purchase
  • And each hydrometer has a laser engraved patent number
  • Fit for brackish and marine aquariums. Perfect for testing both salinity and specific gravity of your brackish and marine tanks.
  • Manufacture: TOPINCN
  • Product Dimensions: 5.51 x 3.54 x 0.79 inches; 3.17 Ounces
  • Editor's Impressions Of The TOPINCN
  • Accuracy [star rating='4.2']
  • Quality [star rating='5']
  • Value For Money [star rating='5']
  • Affordability [star rating='4.4']

TOPINCN Final Thoughts

"Case is nice as well."

The refractor was off out off the box. It works OK but seems pretty flimsy and it's feel that way. I got this to have a more accurate read than the hydrometer. This device is a godsend and so much easier and cleaner to use. Bubbles can greatly affect the reading. Be sure to adjust the focus by turning the eye focal when you first receive. Ambient room light at night is not enough and makes what you're viewing dark.

Overall Score
5.0

[star rating="5"]
(1 Points)

4. Exo Terra Terrarium Hydrometer

User Ratings: 66 5

Exo Terra PT2466 First Impressions

"Great product."

Great product I used for beer making and my saltwater aquarium. I couldn't decide between this and one of the float arm meters or both. For the price you definitley cant beat this meter is great! However, the numbers are soooo small it is sometimes hard to read. 027, I'm so glad I bought this one and it came spot on. Does just as good of a job of any meter you would buy at the store! He is too cute not to want to take care of properly.

  • Exo Terra Terrarium Hydrometer
  • Wipe clean
  • Analog hygrometer
  • Adhere the hygrometer in the terrarium
  • Clear analog dial display
  • Easy to read and install
  • Great for monitoring the humidity levels
  • Manufacture: Exo Terra
  • Product Dimensions: 0.5 x 4.1 x 7 inches; 0.64 Ounces
  • Editor's Impressions Of The Exo Terra PT2466
  • Accuracy [star rating='3.4']
  • Quality [star rating='3.9']
  • Value For Money [star rating='4.9']
  • Affordability [star rating='4.9']

Exo Terra PT2466 Final Thoughts

"Great tool."

I have a 2000+ gallon pond and I just put salt in it last month. Plus it is super easy to use and clean. Bubbles can greatly affect the reading. The water was at what I expected it should be. Does just as good of a job of any meter you would buy at the store! Simple to use, but if there are any air bubbles the results will be way off. Now its easy to make sure I have the correct amount of salt in my aquariums.

Overall Score
4.3

[star rating="4.3"]
(1002 Points)

5. NEW RHS-10ATC 0-10% Salinity Refractometer Salt Water Aquarium

User Ratings: 53 7

Ade Advanced Optics RHS-10ATC First Impressions

"So, it does seem to work."

Definitely a lot cheaper than a refractometer. I bought this refractometer as a more accurate option for salinity than a hydrometer. But there are some ways to keep on getting accurate readings. I bought this salinity meter for my aquarium. Small problem with bubbles on the needle but other than that no issues. The reading is big enough for you to read and it comes with the batteries. I don't know if that's a positive or negative but just different.

  • NEW RHS-10ATC 0-10% Salinity Refractometer Salt Water Aquarium
  • Manufacture: Ade Advanced Optics®
  • Editor's Impressions Of The Ade Advanced Optics RHS-10ATC
  • Accuracy [star rating='3.1']
  • Quality [star rating='4.8']
  • Value For Money [star rating='3.9']
  • Affordability [star rating='3.1']

Ade Advanced Optics RHS-10ATC Final Thoughts

"I recommended!"

I bought this and a hydrometer because of the reviews saying its not accurate. I have gone two years in this hobby with a hydrometer. Very easy, turn screw very slowly to calibrate. Very quick to calibrate and to use. Just give me one simple, accurate reading to go by, and I'm happy. Clear readout with the ability to calibrate and focus. Excellent piece of equipment for the price.

Overall Score
3.9

[star rating="3.9"]
(68 Points)

6. LemonBest 0%-10% Automatic Temperature Compensation Salinity Refractometer Salt Water Aquariu...

User Ratings: 75 5

LemonBest First Impressions

"Great tool."

I don't want to deal with temperature correction or. When I compared it to what my local pet store was reading my water at it was dead on. Used distilled water to calibrate, the screw is located under the rubber cap. This one here was much cheaper,& exactly the same as they sold in the store. At first, I was getting bubbles sticking to the rotating arrow. Definitely a lot cheaper than a refractometer. I decided to upgrade and it was easy to calibrate.

  • LemonBest 0%-10% Automatic Temperature Compensation Salinity Refractometer Salt Water Aquarium by Lemonbest
  • Features with automatic temperature compensation (ATC) function
  • Designed for testing the concentration of salt water and brine, ideal for aquariums, marine monitoring and quality control in research and clinical laboratories
  • With just a couple of drops of aquarium water you know exactly what the salinity is
  • Measures on 2 scales, specific Gravity (D 20/20) and parts per thousand (‰), provides a direct reading of the specific gravity and concentration of salt in water
  • Comes with a hard case, dropper, screwdriver and cleaning cloth
  • Manufacture: Lemonbest
  • Product Dimensions: 7.87 x 1.57 x 1.57 inches; 3.88 Ounces
  • Editor's Impressions Of The LemonBest
  • Accuracy [star rating='5']
  • Quality [star rating='5']
  • Value For Money [star rating='5']
  • Affordability [star rating='5']

LemonBest Final Thoughts

"Easy to use."

Make sure to knock out the bubbles on the white dial by hitting it with your knuckle. It works OK but seems pretty flimsy and it's feel that way. My only criticism would be that it's a little too dark. I don't know if that's a positive or negative but just different. Just rinse with warm water afterwards. I bought this and a hydrometer because of the reviews saying its not accurate. Pretty darn accurate for the price.

Overall Score
4.5

[star rating="4.5"]
(315 Points)

7. Hikari AccuProbe Aquarium Hydrometer, Full

User Ratings: 68 10

Hikari 96010 First Impressions

"Couldn't be happier."

This device is a godsend and so much easier and cleaner to use. Bought this as a back up refractometer. I bought this salinity meter for my aquarium. My corals will be much happier now. I can check the water in 5 seconds without squinting. A hydrometer for making sure you have the right saltwater mix. Pretty darn accurate for the price.

  • Hikari AccuProbe Aquarium Hydrometer, Full
  • "Dry Hands" design avoids contamination of aquarium or water sample
  • Accurate to 0.001 specific gravity and salinity (PPT) measurements
  • Auto-temperature correcting design
  • Designed to give a temperature-corrected reading in warm water aquariums – 68°F to 85°F (20°C to 30°C)
  • Self-leveling, hanging device included
  • Manufacture: Phillips Feed & Pet Supply Natural Balance
  • Product Dimensions: 11 x 1 x 4 inches; 3.2 Ounces
  • Editor's Impressions Of The Hikari 96010
  • Accuracy [star rating='4.8']
  • Quality [star rating='3.8']
  • Value For Money [star rating='3.9']
  • Affordability [star rating='4.9']

Hikari 96010 Final Thoughts

"Easy to use."

There are conversion charts and tables online. If you let it sit in the tank overnight, it definitely gives an accurate reading. Very easy, turn screw very slowly to calibrate. The water was at what I expected it should be. Does just as good of a job of any meter you would buy at the store! If you read the directions in the box for the refractometer it's for freshwater. Used distilled water to calibrate, the screw is located under the rubber cap.

Overall Score
4.3

[star rating="4.3"]
(9 Points)

8. Ade Advanced Optics aaosal-B Automatic Temperature Compensation Sea Water Salinity Refractometer for...

User Ratings: 26 41

Ade Advanced Optics aaosal-B First Impressions

"Be well my friend."

Comes with a nice carrying case for easy and secure transportation. I have gone two years in this hobby with a hydrometer. It says in the instructions to use distilled water. Good quality and simple to use refractometer. The refractor was off out off the box. It is heavy and easy to read in any light. I use this for my 10g brackish and it works ok.

  • Ade Advanced Optics aaosal-B Automatic Temperature Compensation Sea Water Salinity Refractometer for Aquarium, 0% - 10% and 1.0 to 1.070 S.G. Dual Scale Hydrometer, Black
  • Manufacture: Ade Advanced Optics
  • Editor's Impressions Of The Ade Advanced Optics aaosal-B
  • Accuracy [star rating='2.2']
  • Quality [star rating='3.2']
  • Value For Money [star rating='3.5']
  • Affordability [star rating='3.1']

Ade Advanced Optics aaosal-B Final Thoughts

"Couldn't be happier."

Would be nice if stem were slightly larger for easier read. Looks to provide very accurate readings. Works well on my Saltwater Aquarium. I've tried several different refractometers now and they are mostly the same. 027, I'm so glad I bought this one and it came spot on. I use this to check the specific gravity of my marine aquarium. I felt it wasn't accurate which was verified by my LFS.

Overall Score
3.0

[star rating="3"]
(4 Points)

9. 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']

GXSTWU HY-2 Final Thoughts

"Seems pretty solid."

Hate the batteries, but once loaded, it seems to work fine. If you let it sit in the tank overnight, it definitely gives an accurate reading. Like that it comes with everything needed. Get precise salinity readings in moments. I have to recalibrate it ever use though which worries me sometimes. This one read perfect, and the others were completely inaccurate. Plus it is super easy to use and clean.

Overall Score
4.4

[star rating="4.4"]
(265 Points)

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']

Hobein Final Thoughts

"This tool does that."

Even the smallest bubble will throw the measurements way, way off. It came with all that was listed in the in production description. All very easy and I feel as though I am getting an accurate salinity reading. So once your instant ocean shows a measurement. But there are some ways to keep on getting accurate readings. Too that makes it appear too cheap. Excellent piece of equipment for the price.

Overall Score
4.4

[star rating="4.4"]
(290 Points)

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