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
  • Quality
  • Value For Money
  • Affordability

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


(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
  • Quality
  • Value For Money
  • Affordability

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


(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
  • Quality
  • Value For Money
  • Affordability

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


(7 Points)

4. Tiaoyeer Salinity Refractometer with ATC Refractometer for Seawater, Pool, Tank, Testing, Marine, Fi...

User Ratings: 70

Tiaoyeer First Impressions

"Would buy another!"

This refractor should last a good number of years. 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. Definitely a lot cheaper than a refractometer. Clear readout with the ability to calibrate and focus. I HIGHLY recommend this to Aquarists! It is easy to read and perform the procedure in seconds.

  • Tiaoyeer Salinity Refractometer with ATC Refractometer for Seawater, Pool, Tank, Testing, Marine, Fishkeeping, Dual Scale-Specific Gravity 0-100PPT & 1.000-1.070
  • ACCURATE READINGS : The Aquariums refractometer can measure on 2 Scales Aquariums refractometer features Specific Gravity (D 20/20) 1.000-1.070sg and parts per thousand 0-100PPT (1‰=1ppt=1000ppm)
  • ADVANCED AUTOMATIC TEMPERATURE COMPENSATION(ATC)TECHNOLOGY:Adjust Automatically to Compensate for Temperature, Which makes it even easier to get fast results.
  • SIMPLY USE: Using the dropper to take a sample of wort and put it on the prism. Then hold the refractometer up to the light and look scale through the eyepiece.
  • WIDE USE: The Salinity Refractometer is ideal for Marine Monitoring, Aquariums Water Monitoring, Swimming Pool Water Measuring, Lab or Industrious Purposes.
  • PORTABLE SALINITY CONTENT TESTER: Easy to use, sturdy design, compact in size and light in weight, convenient to keep up and carry around.
  • ACCURATE READINGS : The Aquariums refractometer can measure on 2 Scales Aquariums refractometer features Specific Gravity (D 20/20) 1.000-1.070sg and parts per thousand 0-100PPT (1‰=1ppt=1000ppm)
  • ADVANCED AUTOMATIC TEMPERATURE COMPENSATION(ATC)TECHNOLOGY:Adjust Automatically to Compensate for Temperature, Which makes it even easier to get fast results.
  • SIMPLY USE: Using the dropper to take a sample of wort and put it on the prism. Then hold the refractometer up to the light and look scale through the eyepiece.
  • Manufacture: hsydzsy329
  • Product Dimensions: 5.7 x 1.37 x 1.37 inches; 8.78 Ounces
  • Editor's Impressions Of The Tiaoyeer
  • Accuracy
  • Quality
  • Value For Money
  • Affordability

Tiaoyeer Final Thoughts

"Easy to read and use."

Make sure to knock out the bubbles on the white dial by hitting it with your knuckle. The water was at what I expected it should be. It is essential to get some specialized aquarium calibration fluid for 1. I have to recalibrate it ever use though which worries me sometimes. I compared the readings using this hygrometer and the calibrated refractometer. Comes with a nice carrying case for easy and secure transportation. Do not spend money on calibration fluid to calibrate this meter.

Overall Score
4.1


(5 Points)

5. HydroLogic HLTDS DM-2 Industrial Monitor

HydroLogic HLTDS First Impressions

"Case is nice as well."

Don't care much for having to post a review in order to activate warranty. YOU WILL NOT get an accurate reading if there are bubbles on the needle. The water was at what I expected it should be. However, the numbers are soooo small it is sometimes hard to read. Get precise salinity readings in moments. Was calibrated and worked perfect right out of the box. I would suggest purchasing the salt calibration solution.

  • HydroLogic HLTDS DM-2 Industrial Monitor
  • Measures The Flow Of Untreated Water Coming In Versus Purified Water Going Out
  • Comes Equipped With A 1/2" Inlet And 3/8Th Inch Outlet
  • Features An Auto-Off Function To Conserve Battery Power
  • No Assembly Required
  • Manufacture: Hydro-Logic
  • Item Weight: 2.38 pounds
  • Product Dimensions: 7.2 x 5.1 x 1.7 inches
  • Editor's Impressions Of The HydroLogic HLTDS
  • Accuracy
  • Quality
  • Value For Money
  • Affordability

HydroLogic HLTDS Final Thoughts

"Using for my Pacman frog."

Looks to provide very accurate readings. It is a little cheaper made but it works great for the cost! I've checked about 5 times with the hydrometer and each time has been near perfect. Once I figured that out, it works great. I needed this product and it is a lot less expensive than the local aquarium store. Clear readout with the ability to calibrate and focus. Easy to use, easy to clean, easy to read.

Overall Score
5.0


(1 Points)

6. 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
  • Quality
  • Value For Money
  • Affordability

amzdeal Final Thoughts

"Massive peace of mind."

Be sure to adjust the focus by turning the eye focal when you first receive. Even the smallest bubble will throw the measurements way, way off. YOU WILL NOT get an accurate reading if there are bubbles on the needle. I use this to check the specific gravity of my marine aquarium. When I saw the price offered on this one, I decided to buy and I love it. Excellent piece of equipment for the price. Perfrct for someone learning or anyone for that matter.

Overall Score
4.2


(56 Points)

7. ZRM&E Seawater Hydrometer for Aquarium Aquaculture Seawater Densimeter Ocean Hydrometer Salinity Met...

User Ratings: 70 30

ZRM&E First Impressions

"Gave me confidence."

YOU WILL NOT get an accurate reading if there are bubbles on the needle. I have purchased before will buy again! I felt it wasn't accurate which was verified by my LFS. Very quick to calibrate and to use. It says in the instructions to use distilled water. I bought this refractometer as a more accurate option for salinity than a hydrometer. Don't spend your money on calibration solution.

  • ZRM&E Seawater Hydrometer for Aquarium Aquaculture Seawater Densimeter Ocean Hydrometer Salinity Meter for Fish Tank Salinity Specific Gravity Test
  • Made of high quality plastic, aquarium transparent, automatic accurate reading brine hydrometer
  • Accurate, durable and easy to read salt and specific gravity of your marine aquarium, small and waterproof. If the specific gravity is between 1.000-1.019, it indicates that the specific gravity is low; if the specific gravity is between 1.020-1.023, it indicates that the specific gravity is normal; if the specific gravity is between 1.024-1.030, it indicates that the specific gravity is high
  • The external range of the scale indicates salinity (PPT), and the internal range of the scale indicates gravity. And clearly mark the safe area. Application range: 0-40 degrees (1.000-1.030). If the salinity PPT is between 32-40, it indicates that the salinity is high; if the salinity PPT is between 27-31, it indicates that the salinity is normal; if the salinity PPT is between 0-26, it indicates that the salinity hydrometer is low
  • Wide range of applications: Suitable for salt water and sea water fish tanks. Perfect for testing salinity and specific gravity of saltwater and seawater tanks, including solubility and specific gravity scales. Suitable for fresh water and sea water
  • Easy to read swing arm pointer and ultra wide stable base can provide accurate test results
  • Manufacture: DGHP
  • Editor's Impressions Of The ZRM&E
  • Accuracy
  • Quality
  • Value For Money
  • Affordability

ZRM&E Final Thoughts

"Great Product, Thanks!"

YOU WILL NOT get an accurate reading if there are bubbles on the needle. Get precise salinity readings in moments. If you let it sit in the tank overnight, it definitely gives an accurate reading. Compare it with the refractometer and adjust the refractometer so that it matches. Don't care much for having to post a review in order to activate warranty. Even the smallest bubble will throw the measurements way, way off. I would recommend this product to anyone that has a marine aquarium.

Overall Score
3.8


(4 Points)

8. Aquarium Equip UP Glass Saltwater Hydrometer - Reef Soft Coral Salinity Marine Fish Shrimp sea

User Ratings: 55 17

Aquarium Equip D667 UP??????? First Impressions

"No assembly required."

Hate the batteries, but once loaded, it seems to work fine. And it is much more accurate than my old salinity meter. Be sure to buy the calibration solution and test this before use! My only criticism would be that it's a little too dark. It is a little cheaper made but it works great for the cost! It works, we'll i assume it does as i have nothing to compare it to. I was surprise that the product was really cheap compare to the other ones.

  • Aquarium Equip UP Glass Saltwater Hydrometer - Reef Soft Coral Salinity Marine Fish Shrimp sea
  • 1. Easy to use 2. Green indicators are ideal range of water temperature and specific gravity for most salt water / marine aquariums 3. Hydrometer measures specific gravity 4. Need it for raising brine shrimp
  • Manufacture: D667 UP玻璃海水比重計
  • Product Dimensions: 0.8 x 0.8 x 6.2 inches; 0.3 Ounces
  • Editor's Impressions Of The Aquarium Equip D667 UP???????
  • Accuracy
  • Quality
  • Value For Money
  • Affordability

Aquarium Equip D667 UP??????? Final Thoughts

"No assembly required."

I tried it over and over and no bubbles! Easy to use, easy to clean, easy to read. I did NOT calibrate, but am getting accurate readings. Small problem with bubbles on the needle but other than that no issues. Find a good light source to make reading easier. It's a basic but reliable refractomer I use it for my aquariums. This refractor should last a good number of years.

Overall Score
3.8


(8 Points)

9. 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
  • Quality
  • Value For Money
  • Affordability

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


(28 Points)

10. 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
  • Quality
  • Value For Money
  • Affordability

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


(58 Points)

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