Editor's Choice - Our Favorite Instant Aquarium Hydrometers

1. Instant Ocean SeaTest Hydrometer

User Ratings: 59 6

Instant Ocean TK-504 First Impressions

"Calibrate it, use it."

Make your own by simply boiling some water and collecting the condensate. This one here was much cheaper,& exactly the same as they sold in the store. My only criticism would be that it's a little too dark. Normally that gives the more accurate reading. Used distilled water to calibrate, the screw is located under the rubber cap. Once I adjusted the refractometer, my aquarium salinity read 1. Hate the batteries, but once loaded, it seems to work fine.

  • Instant Ocean SeaTest Hydrometer
  • Marine hydrometer: Tests salinity and specific gravity in marine aquariums to help maintain a healthy tank
  • Accurate: Precise, full-range readings - accurate to +/- 0
  • Ready to use: Simply dunk in aquarium to fill with water, then set on level surface to read
  • Easy to read: Clearly marked to show results
  • Extra-wide stabilizer base: Two-color scale with a safe zone for simple results
  • Manufacture: Instant Ocean
  • Item Weight: 0.8 ounces
  • Product Dimensions: 6.3 x 4.2 x 1.3 inches
  • Editor's Impressions Of The Instant Ocean TK-504
  • Accuracy [star rating='3.8']
  • Quality [star rating='3.3']
  • Value For Money [star rating='3.4']
  • Affordability [star rating='4.5']

Instant Ocean TK-504 Final Thoughts

"Good price."

Simple to use, but if there are any air bubbles the results will be way off. The instant ocean hydrometer will always be right. 026 with the new Aquatic Experts fluid. Now its easy to make sure I have the correct amount of salt in my aquariums. Looks to provide very accurate readings. Easy to use, easy to clean, easy to read. My only criticism would be that it's a little too dark.

Overall Score
4.2

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

Peoples Choice - Other Highly Rated Instant Aquarium Hydrometers

2. KKmoon Salinity Refractometer, Handheld Seawater Hydrometers, Optical Salinity Tester, Portable ATC ...

User Ratings: 70 8

KKmoon First Impressions

"Decent case."

Hate the batteries, but once loaded, it seems to work fine. Get precise salinity readings in moments. I have a 2000+ gallon pond and I just put salt in it last month. The hydrometer is good, but I ordered two Shrimp CRS Miniature glass figurine, Clear. So once your instant ocean shows a measurement. All very easy and I feel as though I am getting an accurate salinity reading. The reading is big enough for you to read and it comes with the batteries.

  • KKmoon Salinity Refractometer, Handheld Seawater Hydrometers, Optical Salinity Tester, Portable ATC Refractometer, Dual Scale Saltwater Tester for Aquarium, Seawater, Pool, Fish Tank
  • Measure salt water or salinity of water, ideal for aquariums and marine monitoring.
  • With measurement level for direct reading. Adjustable manual focus, easy to focus and calibrate.
  • Handheld design and non-slip rubber handle for easy operation.
  • Instant Reading Result: Just need 2-3 drops of solution and a few seconds, you can get accurate readings.
  • Built-in automatic temperature compensation(ATC) to get faster results.
  • Manufacture: KKmoon
  • Item Weight: 8.9 ounces
  • Editor's Impressions Of The KKmoon
  • Accuracy [star rating='4.4']
  • Quality [star rating='4']
  • Value For Money [star rating='3.8']
  • Affordability [star rating='4.8']

KKmoon Final Thoughts

"This tool is AMAZING!"

The refractor was off out off the box. I have a 2000+ gallon pond and I just put salt in it last month. Clear readout with the ability to calibrate and focus. I've tried several different refractometers now and they are mostly the same. He is too cute not to want to take care of properly. When I saw the price offered on this one, I decided to buy and I love it. Very easy, turn screw very slowly to calibrate.

Overall Score
4.2

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

3. 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)

4. NEW RHS-10ATC 0-10% Salinity Refractometer Salt Water Aquarium

User Ratings: 53 7

Ade Advanced Optics RHS-10ATC First Impressions

"So, it does seem to work."

Definitely a lot cheaper than a refractometer. I bought this refractometer as a more accurate option for salinity than a hydrometer. But there are some ways to keep on getting accurate readings. I bought this salinity meter for my aquarium. 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. I don't know if that's a positive or negative but just different.

  • NEW RHS-10ATC 0-10% Salinity Refractometer Salt Water Aquarium
  • Manufacture: Ade Advanced Optics®
  • Editor's Impressions Of The Ade Advanced Optics RHS-10ATC
  • Accuracy [star rating='3.1']
  • Quality [star rating='4.8']
  • Value For Money [star rating='3.9']
  • Affordability [star rating='3.1']

Ade Advanced Optics RHS-10ATC Final Thoughts

"I recommended!"

I bought this and a hydrometer because of the reviews saying its not accurate. I have gone two years in this hobby with a hydrometer. Very easy, turn screw very slowly to calibrate. Very quick to calibrate and to use. Just give me one simple, accurate reading to go by, and I'm happy. Clear readout with the ability to calibrate and focus. Excellent piece of equipment for the price.

Overall Score
3.9

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

5. 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)

6. 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)

7. 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)

8. 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)

9. Rhino Clinical Pet (Dog & Cat) Refractometer HR305 (ATC), Urine Specific Test

RHINO TECHNOLOGY First Impressions

"Easy to use."

If you let it sit in the tank overnight, it definitely gives an accurate reading. It's perfectly accurate based on the known calibration fluid. Functions just as it is supposed to. Plenty of info on YouTube and the web if you don't know how. I don't want to deal with temperature correction or. I've tried several different refractometers now and they are mostly the same. YOU WILL NOT get an accurate reading if there are bubbles on the needle.

  • Rhino Clinical Pet (Dog & Cat) Refractometer HR305 (ATC), Urine Specific Test
  • The Rhino Pet refractometer HR305 can be used to read Specific Gravity of Dog Urine, Specific Gravity of Cat Urine,and Serum or Plasma Protein.
  • We provide 2 years quality warranty and customize services for the Pet refractometer.
  • The surface of the refractometer is sprayed with Teflon,It has the characteristics of wear resistance, corrosion resistance, anti-static and anti-adhesion.
  • The Rhino Pet hand-held Refractometer come with portable holster, water bottle, calibration mini-screwdriver, english instruction manual, cleaning cloth, plastic pipette and case.
  • Rhino Pet refractometer with Automatic Temperature Compensation ( 50°F~86°F / 10°C~30°C ).
  • Manufacture: RHINO TECHNOLOGY
  • Editor's Impressions Of The RHINO TECHNOLOGY
  • Accuracy [star rating='5']
  • Quality [star rating='4.4']
  • Value For Money [star rating='5']
  • Affordability [star rating='5']

RHINO TECHNOLOGY Final Thoughts

"Other then that."

I tried it over and over and no bubbles! I don't know if that's a positive or negative but just different. 027, I'm so glad I bought this one and it came spot on. I got this to have a more accurate read than the hydrometer. Looks to provide very accurate readings. I will get one later but for now this will do, since im just starting. And it is much more accurate than my old salinity meter.

Overall Score
5.0

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

10. Ade Advanced Optics aaosal Professional Automatic Temperature Compensation Sea Water Salinity Refrac...

User Ratings: 68

Ade Advanced Optics aaosal First Impressions

"What else can I say."

I've tried several different refractometers now and they are mostly the same. When I saw the price offered on this one, I decided to buy and I love it. The refractor was off out off the box. I would suggest purchasing the salt calibration solution. I don't want to deal with temperature correction or. The product itself is very good quality and the included instructions are very clear. Looks to provide very accurate readings.

  • Ade Advanced Optics aaosal Professional Automatic Temperature Compensation Sea Water Salinity Refractometer for Aquarium, Hydrometer, 0-100 ppt and 1.000-1.070 Salinity S.G.
  • Manufacture: Ade Advanced Optics
  • Editor's Impressions Of The Ade Advanced Optics aaosal
  • Accuracy [star rating='3.5']
  • Quality [star rating='5']
  • Value For Money [star rating='4.5']
  • Affordability [star rating='3.6']

Ade Advanced Optics aaosal Final Thoughts

"Arrived quickly."

This requires repeatedly tapping the arm with a pencil. 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. I have tried others before but this has given me accurate and stable results. I would suggest purchasing the salt calibration solution. It's fast, it's tidy, and it's accurate. When I compared it to what my local pet store was reading my water at it was dead on.

Overall Score
4.5

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

Copyright © 2022 Rob Aquatics — Primer Child WordPress theme by GoDaddy