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']

Here Are Some Other Related Aquarium Hydrometers

2. 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']

3. 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']

4. Coralife Energy Savers ACLAF877 Deep Six Hydrometer

User Ratings: 67 7

Coralife 100108103 First Impressions

"024 and my refracto read."

I found mine was calibrated out of the box. At first, I was getting bubbles sticking to the rotating arrow. Wipe down glass surface to dry it and put it back on the shelf til next time. So once your instant ocean shows a measurement. Does just as good of a job of any meter you would buy at the store! I tried it over and over and no bubbles! Simple to use, but if there are any air bubbles the results will be way off.

• Coralife Energy Savers ACLAF877 Deep Six Hydrometer
• Included components: All Components included in Picture and Description
• Cora life is one of the markets leading manufacturers of premium aquarium products
• Cora life's Hydrometer takes a true water sample at six inch depth
• Easy to read and accurate, this specific gravity meter is designed to give temperature-corrected readings in warm water aquariums
• Coralife is one of the market’s leading manufacturers of premium aquarium products
• Coralife's Hydrometer takes a true water sample at six inch depth
• Specific Gravity and Salinity PPT Scales
• Optimal Specific Gravity / Salinity range indicator on scale
• Manufacture: Central Garden & Pet
• Product Dimensions: 6.69 x 0.79 x 4.72 inches; 3.2 Ounces

• Editor's Impressions Of The Coralife 100108103
• Accuracy [star rating='4.8']
• Quality [star rating='5']
• Value For Money [star rating='4.8']
• Affordability [star rating='4.4']

5. 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']

6. AUTOUTLET Refractometer Saltwater Aquarium for Seawater,Pool,Tank,Testing,Marine Fishkeeping, 0-100P...

User Ratings: 83 2

AUTOUTLET 8541957195 First Impressions

"These seem spot on."

Not sure how accurate it is, but it's a good reference point. Ambient room light at night is not enough and makes what you're viewing dark. If you read the directions in the box for the refractometer it's for freshwater. And it is much more accurate than my old salinity meter. Waterproof if you accidentally drop it in the pool. My corals will be much happier now. It is a little cheaper made but it works great for the cost!

• AUTOUTLET Refractometer Saltwater Aquarium for Seawater,Pool,Tank,Testing,Marine Fishkeeping, 0-100PPT & 1.000-1.070 Salinity Tester with ATC Function Hydrometer Specific Gravity Salinity Meter Kit
• 【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.
• Due to the difference of human focal lengths,when during adjusting, you may just need to rotate in reverse or re-adjust the distance between your eye and the eyepiece.
• It's necessary to keep the surrounding environment with sufficient brightness and suitable temperature during use. Generally,there is no error in the temperature between 10℃-30℃.(50℉-86℉)
• Specific Gravity (D 20/20) and parts per thousand and replaces your poor quality and difficult to read hydrometer.
• Manufacture: AUTOUTLET
• Product Dimensions: 7.87 x 3.54 x 2.36 inches; 8.48 Ounces

• Editor's Impressions Of The AUTOUTLET 8541957195
• Accuracy [star rating='5']
• Quality [star rating='4.2']
• Value For Money [star rating='4.9']
• Affordability [star rating='5']

7. Pen Type Salinity & Temp Meter Measurement Units Checker Quality Tester ATC for Pond Pool Saltwater ...

User Ratings: 36 25

TEKCOPLUS SMTK-49_SOL First Impressions

"So here's the verdict."

Just give me one simple, accurate reading to go by, and I'm happy. This is perfect to keep a check on the salt level in your tank. He is too cute not to want to take care of properly. Bought this as a back up refractometer. Get precise salinity readings in moments. The unit is really easy to calibrate and used. My only criticism would be that it's a little too dark.

• Pen Type Salinity & Temp Meter Measurement Units Checker Quality Tester ATC for Pond Pool Saltwater Aquarium Cooking Seawater Drinking Water (Salinity Meter 70.0ppt + Buffer Sol'n)
• Ideal for checking salt in fish tanks and aquariums, water monitoring, seawater-prepared food solutions, holding tanks and more!
• Measuring Range: Salinity: 0.00~10.0 ppt (NaCL) and 10.1~70.0ppt (NaCL)
• Auto Power-Off Function with disable feature
• °C/°F unit switchable ,Easy one-touch calibration, Waterproof Rating: IP65
• Calibration set: Buffer NaCI 50ppt and calibration guideline
• Manufacture: TekcoPlus Ltd

• Editor's Impressions Of The TEKCOPLUS SMTK-49_SOL
• Accuracy [star rating='3.8']
• Quality [star rating='3.8']
• Value For Money [star rating='2.6']
• Affordability [star rating='3']

8. Dual Scale Salinity Refractometer ATC 0-100ppt (0-10%) & 1.000-1.070 Specific Gravity, Portable Mete...

User Ratings: 76 4

Gain Express RES-10ATC First Impressions

"Documentation is limited."

So once your instant ocean shows a measurement. And always make sure there is no bubbles on the measuring unit. Make sure to knock out the bubbles on the white dial by hitting it with your knuckle. But with alittle persistance I am able to read it. Make your own by simply boiling some water and collecting the condensate. Works great,& comes in a storage box. Trying to turn it by hand won't work.

• 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
• Range: 0-100ppt (0-10% Salinity) and Density/ Specific Gravity 1.000-1.070 1ppt Salinity and 0.001 g/cm3 Density Resolutions
• Water or a salt (brine) refractometer preferred by aquarist, it checks saltwater & brine or salinity of water, best for aquariums and marine monitoring
• True seawater or a salt (brine) refractometer preferred by aquarist
• Calibrate simply by distilled water, comes with free screwdriver for calibration
• Has automatic temperature compensation (ATC) and has built with the highest and finest quality of aluminum & rubbe
• Manufacture: Gain Express Holdings Ltd
• Part Number: REB-32ATC
• Material: ABS Material for Handle
• Item Weight: 9.9 ounces
• Color: 0-10% Salinity
• Batteries Included?: No
• Batteries Required?: No

• Editor's Impressions Of The Gain Express RES-10ATC
• Accuracy [star rating='3.6']
• Quality [star rating='5']
• Value For Money [star rating='5']
• Affordability [star rating='4.4']

9. Seawater Salinity Refractometer,V-Resourcing Automatic Temperature Compensation Sea Water Salinity M...

User Ratings: 64 8

V·RESOURCING COMINHKPR127692 First Impressions

"Good product."

I have tried others before but this has given me accurate and stable results. All very easy and I feel as though I am getting an accurate salinity reading. I did NOT calibrate, but am getting accurate readings. YOU WILL NOT get an accurate reading if there are bubbles on the needle. I run brackish tanks and it works perfectly. 027, I'm so glad I bought this one and it came spot on. Definitely a lot cheaper than a refractometer.

• Seawater Salinity Refractometer,V-Resourcing Automatic Temperature Compensation Sea Water Salinity Measurer for Aquarium, Hydrometer, 0-100ppt & 1.000-1.070 Salinity Specific Gravity
• Automatic Temperature Compensation: 10℃~30℃
• Measuring range: salinity: 0-100 ‰, Specific Gravity : 1.000 to 1.070
• Minimum scale: salinity: 1 ‰, Specific Gravity : 0.001
• Resolution: salinity: ±1‰, Specific Gravity : 0.001 mm
• Perfect for salty water tank and aquarium, seafood water tank, salty pools & spas and etc
• 1*Salinity Refractometer
• 1*Mini-screwdriver
• 1*Pipette
• Manufacture: V-Resourcing
• Product Dimensions: 8 x 3 x 2 inches; 8 Ounces

• Editor's Impressions Of The V·RESOURCING COMINHKPR127692
• Accuracy [star rating='4.1']
• Quality [star rating='3.3']
• Value For Money [star rating='5']
• Affordability [star rating='5']

10. Fluval Sea Hydrometer for Aquarium, Medium

User Ratings: 46 17

Fluval 14356 First Impressions

"Works perfectly."

Hate the batteries, but once loaded, it seems to work fine. Like that it comes with everything needed. There are conversion charts and tables online. Now its easy to make sure I have the correct amount of salt in my aquariums. The product itself is very good quality and the included instructions are very clear. The reading is big enough for you to read and it comes with the batteries. Small problem with bubbles on the needle but other than that no issues.

• Fluval Sea Hydrometer for Aquarium, Medium
• Helps measure specific gravity and salt level in marine aquariums
• Features large, easy to read markings
• Simple design-blends in easily
• Item Package Weight: 0.185
• Manufacture: Fluval
• Item Weight: 0.81 ounces
• Product Dimensions: 1 x 5.5 x 7.9 inches

• Editor's Impressions Of The Fluval 14356
• Accuracy [star rating='3.5']
• Quality [star rating='3']
• Value For Money [star rating='2.7']
• Affordability [star rating='3.1']