Editor's Choice - Our Favorite Saltwater Aquarium Hydrometers

1. 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']

Peoples Choice - Other Highly Rated Saltwater Aquarium Hydrometers

2. RZ Aquariums Salinity Refractometer for Seawater Marine Fish-Keeping, Dual Scales Specific Gravity S...

User Ratings: 74 3

RZ First Impressions

"Great product."

I bought this salinity meter for my aquarium. I needed this product and it is a lot less expensive than the local aquarium store. When I saw the price offered on this one, I decided to buy and I love it. Works well on my Saltwater Aquarium. I was surprise that the product was really cheap compare to the other ones. But there are some ways to keep on getting accurate readings. Too that makes it appear too cheap.

• RZ Aquariums Salinity Refractometer for Seawater Marine Fish-Keeping, Dual Scales Specific Gravity Salinity Meter Hydrometer 0-100ppt & 1.000-1.070, Saltwater Tester with ATC Function
• 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
• Manufacture: RZ

• Editor's Impressions Of The RZ
• Accuracy [star rating='4.5']
• Quality [star rating='5']
• Value For Money [star rating='4.6']
• Affordability [star rating='4.2']

3. TRZ Salinity Refractometer for Aquariums, Marine Monitoring, Saltwater Testing, Dual Sacle 0-100ppt ...

User Ratings: 58 7

TRZ Hamh Optics&Tools First Impressions

"Using for my Pacman frog."

Plus it is super easy to use and clean. Very quick to calibrate and to use. I bought this refractometer as a more accurate option for salinity than a hydrometer. It works, we'll i assume it does as i have nothing to compare it to. I think those reviews just didn't know how to use it properly. Do not spend money on calibration fluid to calibrate this meter. I've tried several different refractometers now and they are mostly the same.

• TRZ Salinity Refractometer for Aquariums, Marine Monitoring, Saltwater Testing, Dual Sacle 0-100ppt Salinity & 1.000-1.070 Specific Gravity Automatic Temperature Compensation.
• 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！
• Manufacture: Hamh Optics&Tools
• Item Weight: 5.6 ounces
• Product Dimensions: 7.48 x 2.17 x 1.38 inches

• Editor's Impressions Of The TRZ Hamh Optics&Tools
• Accuracy [star rating='3.3']
• Quality [star rating='4.6']
• Value For Money [star rating='5']
• Affordability [star rating='4.1']

4. Pen Type Salinity & Temperature Meter ATC NaCl Salt Water Quality Tester for Saltwater Aquarium Hydr...

User Ratings: 49 17

Gain Express 837-2 First Impressions

"Easy to calibrate."

Just rinse with warm water afterwards. I run brackish tanks and it works perfectly. Hate the batteries, but once loaded, it seems to work fine. I tried it over and over and no bubbles! Excellent piece of equipment for the price. The water was at what I expected it should be. 026 and the tank isn't, new animals will go into shock.

• Pen Type Salinity & Temperature Meter ATC NaCl Salt Water Quality Tester for Saltwater Aquarium Hydroponics Food
• MEASURING RANGE: 0~9999 ppm or 10.0ppt~100.0ppt or 0.0%~10.0% or 0.950~1.080 (S.G.) based on NaCl with ±%F.S ±1 digit / ±0.5°C Accuracy
• DISPLAY: Dual Temperature and Salinity in four measurement units (ppm, ppt, %, S.G) / 30 x 18mm LCD Size
• APPLICATION: Salinity measurement in fish pond, tank, aquariums, laboratories, food processing, hydroponics, Aquaculture, and other water monitoring facilities.
• FEATURES: Waterproof IP65 / One touch calibration / Auto power off and Non-Sleep mode disable / Multi points calibration
• POWER SUPPLY / SENSOR : 4 x LR44 button batteries
• User friendly easy to operate with One-touch calibration
• Manufacture: Gain Express Holdings Ltd
• Batteries: 4 LR44 batteries required.

• Editor's Impressions Of The Gain Express 837-2
• Accuracy [star rating='3.2']
• Quality [star rating='4.1']
• Value For Money [star rating='3.2']
• Affordability [star rating='3.8']

Honorable Mentions - More Top Selling Saltwater Aquarium Hydrometers

5. capetsma Salinity Tester, Accurate Sea Hydrometer Aquarium Marine Salinity Meter for Fish Tank Pond ...

User Ratings: 56 11

capetsma First Impressions

"Great Product, Thanks!"

Be sure to adjust the focus by turning the eye focal when you first receive. There are conversion charts and tables online. I have gone two years in this hobby with a hydrometer. Get precise salinity readings in moments. It is a little cheaper made but it works great for the cost! Make your own by simply boiling some water and collecting the condensate. There are conversion charts and tables online.

• capetsma Salinity Tester, Accurate Sea Hydrometer Aquarium Marine Salinity Meter for Fish Tank Pond Water Saltwater Freshwater Specific Gravity Test
• Safe Material & Unique Design: Made of durable Acrylic, this Fish Tank Test Kit salinity Hydrometer is designed with an automatic level function.
• Quickly, easily, and accurately measurement: With this hydrometer saltwater aquarium test kit, you can test your marine aquarium's salt level and specific gravity, and It is optimum to be put into below 6" deep water to avoid the error caused by the oil film on the water.
• Higher Accuracy & safe zone indicated: Readings are temperature-corrected & accurate to +/- 0. 001. specific gravity units ranges from 1. 000 - 1. 030 with a safe zone of 1.020-1.023. The outside range of scale indicates salinity ppt, ranges from 0-40, safe zone is 27-31.
• Easy to Read & Clean: The easy-to-read swing-arm pointer and extra wide stable base provide an accurate test result. After use, soak this saltwater meter in mild acid(vinegar) for 30 minutes, rinse with tap water and air dry. Do not disassemble.
• Wide Usage:Fit for brackish and reef salt marine aquariums. Perfect for testing both salinity and specific gravity of your brackish and marine tank.Includes salinity and specific gravity scales.Suitable for fresh water and sea water.
• Manufacture: Capetsma

• Editor's Impressions Of The capetsma
• Accuracy [star rating='3.4']
• Quality [star rating='3.3']
• Value For Money [star rating='3']
• Affordability [star rating='3.5']

6. Coralife BioCube Mini Aquarium Hydrometer

User Ratings: 37 28

Coralife 100115642 First Impressions

"NO BUBBLES!"

My corals will be much happier now. Every time I leave to do something I come back and it's at the bottom of my tank. And it is much more accurate than my old salinity meter. This device is a godsend and so much easier and cleaner to use. It is a little cheaper made but it works great for the cost! Just give me one simple, accurate reading to go by, and I'm happy. When I saw the price offered on this one, I decided to buy and I love it.

• Coralife BioCube Mini Aquarium Hydrometer
• Can remain submerged inside your aquarium or sump
• Know your salinity in a glance
• Compact design allows for discreet placement in the aquarium
• Ideal for all saltwater aquariums and sumps
• Manufacture: Central Garden & Pet
• Product Dimensions: 3.9 x 1 x 6 inches; 0.8 Ounces

• Editor's Impressions Of The Coralife 100115642
• Accuracy [star rating='3.4']
• Quality [star rating='4.3']
• Value For Money [star rating='2.8']
• Affordability [star rating='3.9']

7. Amzdeal Salinity Refractometer Aquarium & Seawater - Dual Scale (1.0 to 1.070 S.G.)

User Ratings: 66 12

amzdeal First Impressions

"Seems to work fine."

Hate the batteries, but once loaded, it seems to work fine. For the price you definitley cant beat this meter is great! I would recommend this product to anyone that has a marine aquarium. Make sure to knock out the bubbles on the white dial by hitting it with your knuckle. I was surprise that the product was really cheap compare to the other ones. I don't want to deal with temperature correction or. This is perfect to keep a check on the salt level in your tank.

• Amzdeal Salinity Refractometer Aquarium & Seawater - Dual Scale (1.0 to 1.070 S.G.)
• 【Automatic Temperature Compensation】 Hand-held ATC refractometer, can be used in the temperature 5-30 ℃ / 41-86℉
• 【Dual Salinity Scale】Salt content 0 ~ 100 ‰ (0 ~ 10%) and Salt specific gravity 1.000 ~ 1.070sg. Minimum scale is 1 ‰ (0.1%) or 0.001sg, more precise
• 【Easy to Use】Using distilled water to calibrate and then you can measure the saltwater and get the result
• 【Package Content】Come with all the accessories, including Dropper, Screwdriver, Cleaning Cloth, Storage Case and User Manual
• 【Widely Use】This refractometer can be used to measure the salt content or sugar content, good for aquariums and marine monitoring
• Manufacture: Amzdeal

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

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. Aichose Salinity Refractometer for Seawater and Marine Fishkeeping Aquarium, Saltwater Pool, with AT...

User Ratings: 71

aichose SR0024BE First Impressions

"Easy to use."

I use this for my 10g brackish and it works ok. I was surprise that the product was really cheap compare to the other ones. Make sure to knock out the bubbles on the white dial by hitting it with your knuckle. 010; I can easily read this off of the refractometer. I have a 2000+ gallon pond and I just put salt in it last month. I have a 2000+ gallon pond and I just put salt in it last month. It did not need adjusting to calibrate, though I tried to just to see how it worked.

• Aichose Salinity Refractometer for Seawater and Marine Fishkeeping Aquarium, Saltwater Pool, with ATC Function, Dual Scale: Salinity 0-100‰ and Corresponding Specific Gravity
• 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.
• Manufacture: XDC Co,.Ltd.

• Editor's Impressions Of The aichose SR0024BE
• Accuracy [star rating='4.4']
• Quality [star rating='5']
• Value For Money [star rating='5']
• Affordability [star rating='4.3']

10. 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']