Editor's Choice - Our Favorite Gain Express Aquarium Hydrometers

1. 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']

Gain Express 837-2 Final Thoughts

"So, it does seem to work."

But with alittle persistance I am able to read it. Perfrct for someone learning or anyone for that matter. Once I adjusted the refractometer, my aquarium salinity read 1. Works great,& comes in a storage box. Works well on my Saltwater Aquarium. It did not need adjusting to calibrate, though I tried to just to see how it worked. Would be nice if stem were slightly larger for easier read.

Overall Score
3.8

[star rating="3.8"]
(99 Points)

Peoples Choice - Other Highly Rated Gain Express Aquarium Hydrometers

2. 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']

Gain Express RES-10ATC Final Thoughts

"Good product."

For the price you definitley cant beat this meter is great! Now its easy to make sure I have the correct amount of salt in my aquariums. Comes with a nice carrying case for easy and secure transportation. Get precise salinity readings in moments. I have tried others before but this has given me accurate and stable results. Im using it for trying to create water conditions for amano zoes. I couldn't decide between this and one of the float arm meters or both.

Overall Score
4.6

[star rating="4.6"]
(49 Points)

3. Clinical Refractometer with ATC, Tri-Scale Serum Plasma Protein Test 2-14g/dl Urine Specific Gravity...

Gain Express REC-300ATC First Impressions

"Matches my hydrometer."

YOU WILL NOT get an accurate reading if there are bubbles on the needle. If you let it sit in the tank overnight, it definitely gives an accurate reading. Even the smallest bubble will throw the measurements way, way off. It is easy to read and perform the procedure in seconds. Pretty darn accurate for the price. Easy to use, easy to clean, easy to read. Definitely a lot cheaper than a refractometer.

  • Clinical Refractometer with ATC, Tri-Scale Serum Plasma Protein Test 2-14g/dl Urine Specific Gravity 1.000-1.060SG, for Veterinary Vet Cat Dog Pets
  • Animal clinical refractometer Tri Scale for Dog Cat Test of Serum protein and Urine specific gravity
  • TRIPLE SCALE: Dog Scale Urine Specific Gravity is for Large Animal, Cat Scale Urine Specific Gravity is for Small Animal and Serum or Plasma Protein Scale for all animals
  • MEASURING RANGE: Dog and Cat Urine specific gravity: 1.000 - 1.060SG ; Serum Protein: 2-14g/dl
  • Cushioned w/ soft and comfortable non-slip rubberized grip, insulate test solution from body heat
  • Auto Temperature Compensation (ATC), rest easy that your measurements are always accurate regardless of temperature variation
  • Manufacture: Gain Express Holdings Ltd
  • Part Number: REC-300ATC
  • Item Weight: 9.2 ounces
  • Color: Urine Sg / Serum Protein
  • Batteries Included?: No
  • Batteries Required?: No
  • Editor's Impressions Of The Gain Express REC-300ATC
  • Accuracy [star rating='4.2']
  • Quality [star rating='5']
  • Value For Money [star rating='5']
  • Affordability [star rating='4.2']

Gain Express REC-300ATC Final Thoughts

"These seem spot on."

Great tool if you have a salt-water fish tank or a decorative pond. My only criticism would be that it's a little too dark. I decided to upgrade and it was easy to calibrate. Definitely a lot cheaper than a refractometer. Even the smallest bubble will throw the measurements way, way off. Excellent piece of equipment for the price. Small problem with bubbles on the needle but other than that no issues.

Overall Score
5.0

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

4. 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']

TRZ Hamh Optics&Tools Final Thoughts

"Be well my friend."

I found mine was calibrated out of the box. Good quality and simple to use refractometer. I was surprise that the product was really cheap compare to the other ones. Works well on my Saltwater Aquarium. Don't care much for having to post a review in order to activate warranty. Compare it with the refractometer and adjust the refractometer so that it matches. When I compared it to what my local pet store was reading my water at it was dead on.

Overall Score
4.2

[star rating="4.2"]
(112 Points)

5. 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']

Bubble Magus Final Thoughts

"Easy to use."

Functions just as it is supposed to. Be sure to buy the calibration solution and test this before use! Ambient room light at night is not enough and makes what you're viewing dark. It is a little cheaper made but it works great for the cost! I decided to upgrade and it was easy to calibrate. I would recommend this product to anyone that has a marine aquarium. So worth it considering its great quality and great price.

Overall Score
5.0

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

6. Aeroway Salinity Refractometer, Aquarium & Seawater - Dual Scale (1.0 to 1.070 S.G.)

User Ratings: 79 3

Aeroway 8541957182 First Impressions

"021 the other read."

Make sure to knock out the bubbles on the white dial by hitting it with your knuckle. Normally that gives the more accurate reading. I will get one later but for now this will do, since im just starting. I run brackish tanks and it works perfectly. I strongly recommend a refractometer vs. This device is a godsend and so much easier and cleaner to use. On the shaft of the refractometer, there's a little, rubber-covered nub.

  • Aeroway Salinity Refractometer, Aquarium & Seawater - Dual Scale (1.0 to 1.070 S.G.)
  • Measure salt water or salinity of water, ideal for aquariums and marine monitoring.
  • Features automatic temperature compensation (ATC),The main part is made of chromium, it's very durable.
  • Measures on 2 scales, Specific Gravity (D 20/20) and parts per thousand (‰).
  • Comes with hard case, dropper, screwdriver and cleaning cloth.
  • We offer premium quality and the best service, no matter what reason cause dissatisfaction,just return it within 30 days for a full refund. No questions asked, no hassle.
  • Manufacture: Aeroway
  • Editor's Impressions Of The Aeroway 8541957182
  • Accuracy [star rating='3.7']
  • Quality [star rating='4.2']
  • Value For Money [star rating='4.9']
  • Affordability [star rating='4.7']

Aeroway 8541957182 Final Thoughts

"Works great!"

Simple to use, but if there are any air bubbles the results will be way off. I compared the readings using this hygrometer and the calibrated refractometer. Normally that gives the more accurate reading. It's a basic but reliable refractomer I use it for my aquariums. Every time I leave to do something I come back and it's at the bottom of my tank. I bought this and a hydrometer because of the reviews saying its not accurate. So worth it considering its great quality and great price.

Overall Score
4.6

[star rating="4.6"]
(43 Points)

7. Automatic Temperature Compensation Sea Water Salt Salinity Refractometer for Aquarium, 0% - 10% & 1....

User Ratings: 50 10

Ade Advanced Optics Salinity10 First Impressions

"No assembly required."

I use this for my 10g brackish and it works ok. Like that it comes with everything needed. It is essential to get some specialized aquarium calibration fluid for 1. Looks to provide very accurate readings. I was surprise that the product was really cheap compare to the other ones. It is essential to get some specialized aquarium calibration fluid for 1. Hate the batteries, but once loaded, it seems to work fine.

  • Automatic Temperature Compensation Sea Water Salt Salinity Refractometer for Aquarium, 0% - 10% & 1.0 to 1.070 S.g. Dual Scale Hydrometer By Adeadvancedoptics
  • Manufacture: Ade Advanced Optics®
  • Product Dimensions: 8.7 x 2.8 x 1.42 inches; 6.4 Ounces
  • Editor's Impressions Of The Ade Advanced Optics Salinity10
  • Accuracy [star rating='4']
  • Quality [star rating='4.9']
  • Value For Money [star rating='3.3']
  • Affordability [star rating='3.2']

Ade Advanced Optics Salinity10 Final Thoughts

"Easy to use."

Small problem with bubbles on the needle but other than that no issues. This one read perfect, and the others were completely inaccurate. Then I made a mark on it to set the salinity of my fish tank. Great product I used for beer making and my saltwater aquarium. Now that it's calibrated I love it! It's fast, it's tidy, and it's accurate. 026 and the tank isn't, new animals will go into shock.

Overall Score
3.9

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

8. Pet Dog & Cat Refractometer,V-Resourcing Pet Urine Specific Gravity (1.000~1.060) Clinical Refractom...

User Ratings: 79

V·RESOURCING VLT065 First Impressions

"Seems pretty solid."

I found mine was calibrated out of the box. The water was at what I expected it should be. 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's a basic but reliable refractomer I use it for my aquariums. This refractometer came with two scales and Automatic Temperature Compensation. I got this to have a more accurate read than the hydrometer.

  • Pet Dog & Cat Refractometer,V-Resourcing Pet Urine Specific Gravity (1.000~1.060) Clinical Refractometer with Serum or Plasma Protein Test (2~14 g/100ml) for Veterinary Cat,Dog, Pets
  • 1.Hand-Held Pet Urine Specific Gravity Refractometer with Automatic Temperature Compensation(ATC: 10℃~30℃)
  • 2.[ Measuring Range ] Dog Urine Specific Gravity:1.000~1.060 ; Cat Urine Specific Gravity:1.000~1.060 ; Serum or Plasma Protein:2~14 g/100ml
  • 3.[ Easy to use ] Place 2 - 3 drops of sample onto the prism, and then look through the eyepiece for both Brix and Specific Gravity readings
  • 4.[ Convenient to store ] Compact in size and light in weight, packed with a plastic case, convenient to store and carry around
  • 5.[ Application ] This product provides quick and accurate indication of vital fluids levels.Ideal for clinical usage and intended for Veterinary
  • N.W. of a piece: about 102g
  • Product Size:19.5*4*4cm
  • Package Weight:237g
  • Manufacture: V-Resourcing
  • Editor's Impressions Of The V·RESOURCING VLT065
  • Accuracy [star rating='4.8']
  • Quality [star rating='3.9']
  • Value For Money [star rating='5']
  • Affordability [star rating='4.5']

V·RESOURCING VLT065 Final Thoughts

"Massive peace of mind."

I HIGHLY recommend this to Aquarists! I will update later to see if the refractor will keep its calibration. When I saw the price offered on this one, I decided to buy and I love it. Pretty darn accurate for the price. Too that makes it appear too cheap. Small problem with bubbles on the needle but other than that no issues. Bubbles can greatly affect the reading.

Overall Score
4.7

[star rating="4.7"]
(28 Points)

9. 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']

capetsma Final Thoughts

"Easy to use."

Be sure to buy the calibration solution and test this before use! If you let it sit in the tank overnight, it definitely gives an accurate reading. Plenty of info on YouTube and the web if you don't know how. Works great,& comes in a storage box. Hate the batteries, but once loaded, it seems to work fine. Too that makes it appear too cheap. So worth it considering its great quality and great price.

Overall Score
4.0

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

10. 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']

Hongzer Final Thoughts

"So far so good."

It is a little cheaper made but it works great for the cost! Pretty darn accurate for the price. Ambient room light at night is not enough and makes what you're viewing dark. Normally that gives the more accurate reading. Now its easy to make sure I have the correct amount of salt in my aquariums. I was surprise that the product was really cheap compare to the other ones. This refractor should last a good number of years.

Overall Score
5.0

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

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