Editor's Choice - Our Favorite KOOBOOK Aquarium Hydrometers

1. KOOBOOK 1 Pcs Accurate Hydrometer Salinity Meter 1.000-1.027 Salinity Range 0-36 for Aquarium Fish T...

User Ratings: 44 27

KOOBOOK First Impressions

"0, it reads 1."

Not sure how accurate it is, but it's a good reference point. I will get one later but for now this will do, since im just starting. It is heavy and easy to read in any light. Find a good light source to make reading easier. It works, we'll i assume it does as i have nothing to compare it to. If you read the directions in the box for the refractometer it's for freshwater. Good quality and simple to use refractometer.

  • KOOBOOK 1 Pcs Accurate Hydrometer Salinity Meter 1.000-1.027 Salinity Range 0-36 for Aquarium Fish Tank Marine Sea Saltwater
  • Made of high quality plastic, Withstand voltage,high transparency.
  • Special for culture of marine fish, the specific gravity and salinity of seawater are displayed once, easy to use and easy to read.
  • Keeping your hands clean,go underwater 15 cm (6 inch) depth to avoid errors caused by inhalation of oil film on the top of water.
  • When the water reaches full state (with the top of the baffle level), filed a hydrometer, this product can be hand or hang in the cylinder, automatic level function, can automatically find out the level to avoid the error.
  • Proper salinity level is one of the most important factors in the health of the fish.Readable and accuracy can up to ± 0.002 gravity unit.
  • Manufacture: KOOBOOK
  • Editor's Impressions Of The KOOBOOK
  • Accuracy [star rating='2.7']
  • Quality [star rating='2.8']
  • Value For Money [star rating='2.7']
  • Affordability [star rating='2.7']

KOOBOOK Final Thoughts

"This tool does that."

It works, we'll i assume it does as i have nothing to compare it to. But with alittle persistance I am able to read it. I have purchased before will buy again! I have to recalibrate it ever use though which worries me sometimes. This requires repeatedly tapping the arm with a pencil. I would suggest purchasing the salt calibration solution. The reading is big enough for you to read and it comes with the batteries.

Overall Score
3.3

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

2. 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)

3. Kocome Marine Hydrometer Reef Fish Tank Aquarium Water Salinity Specific Gravity Tester

User Ratings: 71

Kocome First Impressions

"Great kit."

I use this for my 10g brackish and it works ok. Plus it is super easy to use and clean. I did NOT calibrate, but am getting accurate readings. I needed this product and it is a lot less expensive than the local aquarium store. It's fast, it's tidy, and it's accurate. But with alittle persistance I am able to read it. Don't care much for having to post a review in order to activate warranty.

  • Kocome Marine Hydrometer Reef Fish Tank Aquarium Water Salinity Specific Gravity Tester
  • Accurate and easy to read.
  • Size: 3.54×4.72×0.59in (Approx.).
  • Readings are temperature-corrected & accurate to +/- 0. 002 specific gravity units which range from 1. 000 - 1. 030 specific gravity.
  • It is optimum to be put into below 6" deep water, so it can avoid the error from the oil slick.
  • Perfect for testing both salinity and specific gravity of your brackish and marine tank.
  • Manufacture: KOCOME
  • Editor's Impressions Of The Kocome
  • Accuracy [star rating='3.6']
  • Quality [star rating='4.2']
  • Value For Money [star rating='4']
  • Affordability [star rating='3.9']

Kocome Final Thoughts

"026 as expected."

I would recommend you to purchase this and skip the other ones. I have tried others before but this has given me accurate and stable results. On the shaft of the refractometer, there's a little, rubber-covered nub. I couldn't decide between this and one of the float arm meters or both. Very easy, turn screw very slowly to calibrate. Looks to provide very accurate readings. The instant ocean hydrometer will always be right.

Overall Score
4.6

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

4. 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)

5. AUTOUTLET Refractometer Saltwater Aquarium for Seawater,Pool,Tank,Testing,Marine Fishkeeping, 0-100P...

User Ratings: 83 2

AUTOUTLET 8541957195 First Impressions

"These seem spot on."

Not sure how accurate it is, but it's a good reference point. Ambient room light at night is not enough and makes what you're viewing dark. If you read the directions in the box for the refractometer it's for freshwater. And it is much more accurate than my old salinity meter. Waterproof if you accidentally drop it in the pool. My corals will be much happier now. It is a little cheaper made but it works great for the cost!

  • AUTOUTLET Refractometer Saltwater Aquarium for Seawater,Pool,Tank,Testing,Marine Fishkeeping, 0-100PPT & 1.000-1.070 Salinity Tester with ATC Function Hydrometer Specific Gravity Salinity Meter Kit
  • 【Salinity Refractometer】Measure Salt Water or Salinity of Water,Monitor and Control the Concentration of Salt Water and Brine,Ideal for Aquariums and Marine Applications.
  • 【Measures on 2 Scales】Specific Gravity (D 20/20) and parts per thousand and replaces your poor quality and difficult to read hydrometer.
  • 【Density Measurement Range】1.0-1.070, Minimum Scale is 0.001.
  • 【Concentration Measurement Range】0-100‰, Minimum Scale is 1‰.
  • 【ATC】Automatic Temperature Compensation, 0-10°C.
  • Due to the difference of human focal lengths,when during adjusting, you may just need to rotate in reverse or re-adjust the distance between your eye and the eyepiece.
  • It's necessary to keep the surrounding environment with sufficient brightness and suitable temperature during use. Generally,there is no error in the temperature between 10℃-30℃.(50℉-86℉)
  • Specific Gravity (D 20/20) and parts per thousand and replaces your poor quality and difficult to read hydrometer.
  • Manufacture: AUTOUTLET
  • Product Dimensions: 7.87 x 3.54 x 2.36 inches; 8.48 Ounces
  • Editor's Impressions Of The AUTOUTLET 8541957195
  • Accuracy [star rating='5']
  • Quality [star rating='4.2']
  • Value For Money [star rating='4.9']
  • Affordability [star rating='5']

AUTOUTLET 8541957195 Final Thoughts

"2 failed, 3 did not."

Just rinse with warm water afterwards. I bought this and a hydrometer because of the reviews saying its not accurate. Now that it's calibrated I love it! I HIGHLY recommend this to Aquarists! I have purchased before will buy again! I got this to have a more accurate read than the hydrometer. Too that makes it appear too cheap.

Overall Score
4.7

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

6. 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)

7. AUTOUTLET Salinity Refractometer for Aquarium Salinity Tester with ATC and Dual Scale 0-100‰ & 1.0...

User Ratings: 89

AUTOUTLET First Impressions

"Better than nothing."

027, I'm so glad I bought this one and it came spot on. Then I made a mark on it to set the salinity of my fish tank. Once I adjusted the refractometer, my aquarium salinity read 1. If you let it sit in the tank overnight, it definitely gives an accurate reading. It's a basic but reliable refractomer I use it for my aquariums. I think those reviews just didn't know how to use it properly. Used distilled water to calibrate, the screw is located under the rubber cap.

  • AUTOUTLET Salinity Refractometer for Aquarium Salinity Tester with ATC and Dual Scale 0-100‰ & 1.000-1.070 Specific Gravity Saltwater Tester for Seawater Pool Fish Tank
  • Dual scale display provides readings of one-thousandth (0-100PPT) and specific gravity (1.000 to 1.070 SG), and replace the hydrometer for easier and more accurate measurement.
  • Automatic temperature compensation. With the help of the ATC function, the salt water tester can automatically compensate for changes in the ambient temperature, which can obtain accurate readings faster and more easily.
  • Durable and portable, the salt water tester is made of non-staining, non-corrosive and non-reactive aluminum material, with superb technology, strong and durable, light weight and easy to carry.
  • Widely used, can be used for aquarium, marine monitoring, agriculture, horticulture and educational purposes (biological projects).
  • Easy to use, salinity refractometer is easy to operate, only 2 drops of sample after calibration can get accurate reading through eyepiece.
  • Due to the difference of human focal lengths,when during adjusting, you may just need to rotate in reverse or re-adjust the distance between your eye and the eyepiece.
  • It's necessary to keep the surrounding environment with sufficient brightness and suitable temperature during use. Generally,there is no error in the temperature between 10℃-30℃.(50℉-86℉)
  • Specific Gravity (D 20/20) and parts per thousand and replaces your poor quality and difficult to read hydrometer.
  • Manufacture: AUTOUTLET
  • Editor's Impressions Of The AUTOUTLET
  • Accuracy [star rating='4']
  • Quality [star rating='4.3']
  • Value For Money [star rating='5']
  • Affordability [star rating='5']

AUTOUTLET Final Thoughts

"Arrived quickly."

It works, we'll i assume it does as i have nothing to compare it to. For the price you definitley cant beat this meter is great! If you read the directions in the box for the refractometer it's for freshwater. Im using it for trying to create water conditions for amano zoes. 027, I'm so glad I bought this one and it came spot on. 027, I'm so glad I bought this one and it came spot on. Even the smallest bubble will throw the measurements way, way off.

Overall Score
4.9

[star rating="4.9"]
(14 Points)

8. LemonBest 0%-10% Automatic Temperature Compensation Salinity Refractometer Salt Water Aquariu...

User Ratings: 75 5

LemonBest First Impressions

"Great tool."

I don't want to deal with temperature correction or. When I compared it to what my local pet store was reading my water at it was dead on. Used distilled water to calibrate, the screw is located under the rubber cap. This one here was much cheaper,& exactly the same as they sold in the store. At first, I was getting bubbles sticking to the rotating arrow. Definitely a lot cheaper than a refractometer. I decided to upgrade and it was easy to calibrate.

  • LemonBest 0%-10% Automatic Temperature Compensation Salinity Refractometer Salt Water Aquarium by Lemonbest
  • Features with automatic temperature compensation (ATC) function
  • Designed for testing the concentration of salt water and brine, ideal for aquariums, marine monitoring and quality control in research and clinical laboratories
  • With just a couple of drops of aquarium water you know exactly what the salinity is
  • Measures on 2 scales, specific Gravity (D 20/20) and parts per thousand (‰), provides a direct reading of the specific gravity and concentration of salt in water
  • Comes with a hard case, dropper, screwdriver and cleaning cloth
  • Manufacture: Lemonbest
  • Product Dimensions: 7.87 x 1.57 x 1.57 inches; 3.88 Ounces
  • Editor's Impressions Of The LemonBest
  • Accuracy [star rating='5']
  • Quality [star rating='5']
  • Value For Money [star rating='5']
  • Affordability [star rating='5']

LemonBest Final Thoughts

"Easy to use."

Make sure to knock out the bubbles on the white dial by hitting it with your knuckle. It works OK but seems pretty flimsy and it's feel that way. My only criticism would be that it's a little too dark. I don't know if that's a positive or negative but just different. Just rinse with warm water afterwards. I bought this and a hydrometer because of the reviews saying its not accurate. Pretty darn accurate for the price.

Overall Score
4.5

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

9. 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)

10. emours Aquarium Gloves Waterproof Elbow Length Long Sleeve Scratch Resistant Work Gloves 27-Inch

User Ratings: 71 6

emours First Impressions

"Great product."

At first, I was getting bubbles sticking to the rotating arrow. I decided to upgrade and it was easy to calibrate. The water was at what I expected it should be. Pretty darn accurate for the price. I don't want to deal with temperature correction or. Wipe down glass surface to dry it and put it back on the shelf til next time. When I'm testing my aquarium water, I want immediate, clear results.

  • emours Aquarium Gloves Waterproof Elbow Length Long Sleeve Scratch Resistant Work Gloves 27-Inch
  • Material: Polyvinyl chloride (PVC) + knit cloth; durable
  • PVC material is chemical and scratch resistant. With velvet inner, can keep your hand warm even in the cold water environment.
  • 27-Inch extra long design. Can keep your hand from getting wet inside the tank .Hand portion size:18x12.5cm/ 7 x 4.9inch ( L x W) ,one size fits most all(medium to large size); with elasticated cuffs, protects hands and arms up to the shoulder;
  • Thicken material,fully lined,waterproof. Keep your hands and arm dry when changing fish tank water, also can prevent allergies, cuts during aqua maintenance;
  • Multifunctional. Can be used in aquarium cleaning, also can be used in aquatic seafood fishing operations.
  • Manufacture: Kensid
  • Editor's Impressions Of The emours
  • Accuracy [star rating='3.7']
  • Quality [star rating='3.5']
  • Value For Money [star rating='4.5']
  • Affordability [star rating='4.3']

emours Final Thoughts

"Great price."

My only criticism would be that it's a little too dark. This one here was much cheaper,& exactly the same as they sold in the store. Make sure to knock out the bubbles on the white dial by hitting it with your knuckle. Calibrate with distilled water and test every so often. At first, I was getting bubbles sticking to the rotating arrow. Now that it's calibrated I love it! Compare it with the refractometer and adjust the refractometer so that it matches.

Overall Score
4.4

[star rating="4.4"]
(40 Points)

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