Editor's Choice - Our Favorite RZ Aquarium Hydrometers

1. 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']

RZ Final Thoughts

"Seems to work fine."

I will get one later but for now this will do, since im just starting. Comes with a nice carrying case for easy and secure transportation. I decided to upgrade and it was easy to calibrate. Plenty of info on YouTube and the web if you don't know how. Small problem with bubbles on the needle but other than that no issues. The reading is big enough for you to read and it comes with the batteries. Be sure to adjust the focus by turning the eye focal when you first receive.

Overall Score
4.6

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

Peoples Choice - Other Highly Rated RZ Aquarium Hydrometers

2. Pet Dog Cat Refractometer Pet Urine Specific Gravity Refractometer Serum Plasma Protein: 2~14g/dl, C...

User Ratings: 66 16

RZ First Impressions

"Clear directions."

Trying to turn it by hand won't work. The water was at what I expected it should be. I would recommend this product to anyone that has a marine aquarium. The instant ocean hydrometer will always be right. And it is much more accurate than my old salinity meter. This requires repeatedly tapping the arm with a pencil. Bubbles can greatly affect the reading.

  • Pet Dog Cat Refractometer Pet Urine Specific Gravity Refractometer Serum Plasma Protein: 2~14g/dl, Clinical Animal Refractometer Hydrometers Urine Tester 1.000-1.060SG for Veterinary Cat Dog Pets
  • TRIPLE SCALES REFRACTOMETER: Left scale for testing urine specific gravity of large animals such as dog, the middle scale can measure cats urine specific gravity or other small animals, the right scale tests serum or plasma protein level for all animals.
  • QUICK & EASY OPERATION: few sample than other lab hydrometers, just 2 or 3 drops of solution and wait for a few seconds, accurate data automatic shows, automatic temperature compensation 0°C-30°C/50°F to 86°F
  • MEASURING RANGE: Serum or plasma protein: 2-14g/dl, large animal like dog and small animals like cats’ urine specific gravity 1.000~1.060 SG, resolution: 0.001SG. Ideal for your home pets, clinical veterinary and pet owners.
  • DURABLE REFRACOMTER: comfortable holding and non-slip ABS rubberized grip, anti-rust aluminum body for long term using. Strictly quality and safety standards approved.
  • COMPACT SIZE: Lightweight and pocket size lab refractometer, comes with sturdy plastic box, mini screwdriver, pipette and wiping cloth and manual packed together, easy to carry and storage.
  • Manufacture: RZ
  • Editor's Impressions Of The RZ
  • Accuracy [star rating='4.5']
  • Quality [star rating='5']
  • Value For Money [star rating='4.7']
  • Affordability [star rating='3.9']

RZ Final Thoughts

"These seem spot on."

I have tried others before but this has given me accurate and stable results. Now that it's calibrated I love it! I use this to check the specific gravity of my marine aquarium. Looks to provide very accurate readings. Get precise salinity readings in moments. Make your own by simply boiling some water and collecting the condensate. I use this for my 10g brackish and it works ok.

Overall Score
4.0

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

3. 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']

UEETEK Final Thoughts

"Nice product!"

So once your instant ocean shows a measurement. When I saw the price offered on this one, I decided to buy and I love it. There are conversion charts and tables online. Make sure to knock out the bubbles on the white dial by hitting it with your knuckle. Small problem with bubbles on the needle but other than that no issues. Like that it comes with everything needed. Don't spend your money on calibration solution.

Overall Score
3.1

[star rating="3.1"]
(3 Points)

4. 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)

5. 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)

6. Digital Salinity Tester for Salt Water - Aquarium Salinity Meter with ATC, IP67 Waterproof, 0-200 PP...

CIZTADA First Impressions

"Works great for reefing!"

Functions just as it is supposed to. Looks to provide very accurate readings. Waterproof if you accidentally drop it in the pool. Does just as good of a job of any meter you would buy at the store! I have a 2000+ gallon pond and I just put salt in it last month. Comes with a nice carrying case for easy and secure transportation. Good quality and simple to use refractometer.

  • Digital Salinity Tester for Salt Water - Aquarium Salinity Meter with ATC, IP67 Waterproof, 0-200 PPT Large Range Multi-Parameter Tester for Seawater, Fish Tank, Hydroponics
  • [Large Salinity Range] Ciztada salinity tester has 2 measurement modes, scale range: 0~9999 ppm/10.0~200 ppt and 0.00-25.00%, which is 2 times than the salinity refractometer
  • [Automatic Temperature Compensation] Ciztada salinity tester is equipped with ATC part inside, during normal temperature, once calibrated, the temperature change would never affect the accurate of your measuring result. This makes it more convenient to use in different temperature
  • [Easy Reading with LCD Backlight] There is no need to worry about seeing the displayed value if the light is insufficient. Ciztada salinity meter features a green backlit LCD to help you see the measurement results clearly in any situation
  • [Multifunctional Salinity tester]: The Ciztada multi-parameter Tester can test Salinity, TDS, EC and Temperature in an accurate, quick and reliable manner for most regular water solutions' testing. Support One-tap switch from salinity to TDS/EC
  • [Wide Applications]: Measures saltwater or salinity of water, ideal for aquarium, marine monitoring, salty pools & spas, koi fish pond, hydroponics and etc
  • Manufacture: CIZTADA
  • Batteries: 3 LR44 batteries required. (included)
  • Editor's Impressions Of The CIZTADA
  • Accuracy [star rating='5']
  • Quality [star rating='4.6']
  • Value For Money [star rating='4.6']
  • Affordability [star rating='5']

CIZTADA Final Thoughts

"Accurate so far!"

Too that makes it appear too cheap. It says in the instructions to use distilled water. This is perfect to keep a check on the salt level in your tank. Normally that gives the more accurate reading. Once I adjusted the refractometer, my aquarium salinity read 1. Bought this one to check my old one, this one checked right on the dot at 1. Bought this one to check my old one, this one checked right on the dot at 1.

Overall Score
5.0

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

7. Abuycs Salinity Refractometer for Seawater and Marine Fishkeeping Aquarium, Saltwater Tester Hydrome...

User Ratings: 86

Abuycs First Impressions

"This tool is AMAZING!"

I have gone two years in this hobby with a hydrometer. I will get one later but for now this will do, since im just starting. The unit is really easy to calibrate and used. I use this for my 10g brackish and it works ok. My meter came already calibrated to 0. The instant ocean hydrometer will always be right. Works well on my Saltwater Aquarium.

  • Abuycs Salinity Refractometer for Seawater and Marine Fishkeeping Aquarium, Saltwater Tester Hydrometer, Dual Sacle 0-100ppt & 1.000-1.070 Specific Gravity with ATC Automatic Temperature Compensation
  • ✅DUAL SCALE MEASURES SALT PERCENT AND SG:Specific gravity,range: 1.000-1.070 g/cm3, resolution: 0.001 g/cm3.Salt percent, range: 0-100 ppt ( or say parts per thousand), resolution: 1 ppt.It is designed for the measurement of seawater (marine aquaria) or very low concentrated salt solutions.
  • ✅ ENDLESS APPLICATION AND EASY TO USE,:Ideal for testing and monitoring aquariums,fish tank, saltwater pool,seawater.Just need 2-3 drops of solution, you can get accurate readings. No batteries needed.
  • ✅ATC TECHNOLOGY:Handheld Salinity Refractometerr with Automatic Temperature Compensation(ATC),no more worry about the temperature change will influence the reading accuracy.the fish keeping refractometer will account for changes in ambient temperature and automatically compensate accordingly to provides accurate and repeatable measurements.
  • ✅AIRCRAFT ALUMIUM BODY MATERIAL:The aquarium refractometer is made of non-staining, non-corrosive and non-reactive aluminum which is lightweight to carry,anti-scratch and durable.
  • ✅WIDE APPLICATION: It is for measuring the salinity of salt water quickly and accurately, ideal for agriculture, industry and research application, such as mariculture, fish culture, aquarium, marine survey, water quality monitoring, salt production, manufacture of normal saline, salinity measurement in food processing etc. Can also be used for medical institutions, university research and so on.
  • Manufacture: Rockgood ltd.
  • Editor's Impressions Of The Abuycs
  • Accuracy [star rating='4']
  • Quality [star rating='5']
  • Value For Money [star rating='5']
  • Affordability [star rating='5']

Abuycs Final Thoughts

"Easy instructions."

The refractor was off out off the box. However, the numbers are soooo small it is sometimes hard to read. I needed this product and it is a lot less expensive than the local aquarium store. Don't spend your money on calibration solution. However, the numbers are soooo small it is sometimes hard to read. Works well on my Saltwater Aquarium. 027, I'm so glad I bought this one and it came spot on.

Overall Score
4.6

[star rating="4.6"]
(10 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. TOPINCN Square Saltwater Hydrometer Salt Water Salinity Meter Accurate Automatic Hydrometer Salt Wat...

TOPINCN First Impressions

"Super easy to use."

Then I made a mark on it to set the salinity of my fish tank. This device is a godsend and so much easier and cleaner to use. 027, I'm so glad I bought this one and it came spot on. I would recommend you to purchase this and skip the other ones. This refractor should last a good number of years. Find a good light source to make reading easier. Just rinse with warm water afterwards.

  • TOPINCN Square Saltwater Hydrometer Salt Water Salinity Meter Accurate Automatic Hydrometer Salt Water Salinity Meter for Fish Tank
  • Accurate, durable, and easy to read sea water hydrometer
  • This product is designed with an automatic level function, can automatically identify the level to avoid errors
  • Very accurate measurement readings, please rest assured to purchase
  • And each hydrometer has a laser engraved patent number
  • Fit for brackish and marine aquariums. Perfect for testing both salinity and specific gravity of your brackish and marine tanks.
  • Manufacture: TOPINCN
  • Product Dimensions: 5.51 x 3.54 x 0.79 inches; 3.17 Ounces
  • Editor's Impressions Of The TOPINCN
  • Accuracy [star rating='4.2']
  • Quality [star rating='5']
  • Value For Money [star rating='5']
  • Affordability [star rating='4.4']

TOPINCN Final Thoughts

"Case is nice as well."

The refractor was off out off the box. It works OK but seems pretty flimsy and it's feel that way. I got this to have a more accurate read than the hydrometer. This device is a godsend and so much easier and cleaner to use. Bubbles can greatly affect the reading. Be sure to adjust the focus by turning the eye focal when you first receive. Ambient room light at night is not enough and makes what you're viewing dark.

Overall Score
5.0

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

10. 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']

aichose SR0024BE Final Thoughts

"Gave me confidence."

I would like to provide a great marine environment for sea-fishes. It's perfectly accurate based on the known calibration fluid. I would suggest purchasing the salt calibration solution. Great little device to check your salt water levels in the swimming pool or spa. A hydrometer for making sure you have the right saltwater mix. I would like to provide a great marine environment for sea-fishes. I bought this and a hydrometer because of the reviews saying its not accurate.

Overall Score
4.5

[star rating="4.5"]
(37 Points)

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