Editor's Choice - Our Favorite ZRM&E Aquarium Hydrometers

1. 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 [star rating='2.9']
  • Quality [star rating='3.8']
  • Value For Money [star rating='4']
  • Affordability [star rating='3.2']

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

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

2. 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 [star rating='2.9']
  • Quality [star rating='3.8']
  • Value For Money [star rating='4']
  • Affordability [star rating='3.2']

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

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

3. 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 [star rating='3.7']
  • Quality [star rating='3.2']
  • Value For Money [star rating='4.8']
  • Affordability [star rating='5']

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

[star rating="4.1"]
(5 Points)

4. 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']

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

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

5. 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']

Coralife 100115642 Final Thoughts

"I say it works very well."

Waterproof if you accidentally drop it in the pool. Do not spend money on calibration fluid to calibrate this meter. I use this for my 10g brackish and it works ok. I use this for my 10g brackish and it works ok. There are conversion charts and tables online. Wipe down glass surface to dry it and put it back on the shelf til next time. I would recommend you to purchase this and skip the other ones.

Overall Score
3.3

[star rating="3.3"]
(57 Points)

6. 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 [star rating='4.3']
  • Quality [star rating='5']
  • Value For Money [star rating='4.5']
  • Affordability [star rating='4.7']

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

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

7. 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)

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']

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)

9. Digital Salinity Meter, SA287 Portable Digital Salinity Meter High Precision Salinity Temperature Pe...

Jadpes First Impressions

"Works great for reefing!"

At first, I was getting bubbles sticking to the rotating arrow. Perfrct for someone learning or anyone for that matter. Works great,& comes in a storage box. Then I made a mark on it to set the salinity of my fish tank. Bubbles can greatly affect the reading. I tried it over and over and no bubbles! I think those reviews just didn't know how to use it properly.

  • Digital Salinity Meter, SA287 Portable Digital Salinity Meter High Precision Salinity Temperature Pen Type Tester for Saltwater, Swimming Pool, Aquaculture, Aquarium
  • WATERPROOF SALINITY METER:It displays the salinity value precisely, compact size and light weight, easy and portable to carry, convenient to use.This instrument can not only detect the salt content of edible salt, salt water pool and koi fish pond, but also the salinity of seawater, marine, salt water fish tank salt level testing.
  • SALINITY TESTER:Digital Salinity Tester for Salt Water.The pen type salinity meter is a precision instrument for testing the salinity value of a solution.Quick and reliable manner for most regular water solutions' testing.
  • WIDE APPLICATIONS:Suitable for saltwater, swimming pool, aquaculture, aquarium (seawater) and pond, food processing and health care products industry. Saltwater Tester for Seawater, Aquariums, Marine Monitoring.
  • BACKLIT DESIGN:It adopts large screen LCD, PPT standard unit display, power display, power data protection function, automatic temperature compensation, dustproof and waterproof functions.
  • APPLICATION:Its full-featured performance, easy operation and replaceable electrodes make it the best choice for rapid, accurate salinity testing in laboratories, sites and schools.
  • Manufacture: Jadpes
  • Product Dimensions: 0.39 x 0.39 x 0.39 inches; 5.29 Ounces
  • Editor's Impressions Of The Jadpes
  • Accuracy [star rating='3.3']
  • Quality [star rating='2.9']
  • Value For Money [star rating='3']
  • Affordability [star rating='2.7']

Jadpes Final Thoughts

"Couldn't do without it."

YOU WILL NOT get an accurate reading if there are bubbles on the needle. It did not need adjusting to calibrate, though I tried to just to see how it worked. This is perfect to keep a check on the salt level in your tank. Make sure to knock out the bubbles on the white dial by hitting it with your knuckle. My only criticism would be that it's a little too dark. It is essential to get some specialized aquarium calibration fluid for 1. I have purchased before will buy again!

Overall Score
3.0

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

10. Accurate Automatic Hydrometer Salt Water Salinity Meter Salinimeter for Fish Tank (Square Type)

User Ratings: 63 16

YOSOO123 First Impressions

"Seems to work fine."

It is a little cheaper made but it works great for the cost! Now that it's calibrated I love it! I got this to have a more accurate read than the hydrometer. I decided to upgrade and it was easy to calibrate. I will get one later but for now this will do, since im just starting. Now that it's calibrated I love it! Plus it is super easy to use and clean.

  • Accurate Automatic Hydrometer Salt Water Salinity Meter Salinimeter for Fish Tank (Square Type)
  • 15 centimeters (6 inches) from the bottom of the water to avoid the error caused by the oil film on the water.
  • Keeping your hands clean and can prevent pollution of water from the fish pond.
  • It is easy to read and the precision can be + (-) 0.001 units of specific gravity. Professional design make it able to get accurate reading when the temperature of the fishpond is at 18 degrees -28 degrees
  • Fish pool, both inside and outside the cylinder can be read. The hydrometer that can float on the surface of the water is simple and easy to read.
  • The proportion of water sample can be automatically detected. The proportion, salinity and conductivity of sea water are shown once.
  • Manufacture: Yosoo123
  • Part Number: Yosoo537gtqix12
  • Item Weight: 3.24 ounces
  • Product Dimensions: 5.51 x 3.54 x 0.79 inches
  • Style: Square Type
  • Batteries Included?: No
  • Batteries Required?: No
  • Editor's Impressions Of The YOSOO123
  • Accuracy [star rating='4.2']
  • Quality [star rating='4.4']
  • Value For Money [star rating='3.4']
  • Affordability [star rating='4.5']

YOSOO123 Final Thoughts

"0, it reads 1."

I use this for my 10g brackish and it works ok. I have purchased before will buy again! Would be nice if stem were slightly larger for easier read. I have gone two years in this hobby with a hydrometer. It is easy to read and perform the procedure in seconds. Ambient room light at night is not enough and makes what you're viewing dark. I have a 2000+ gallon pond and I just put salt in it last month.

Overall Score
4.0

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

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