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The Top Water Testing Kits for Aquariums

woman testing aquarium water for nitrite in a test tube

You may not think that testing the water in your fish tank is a necessary part of owning a home aquarium, but it’s actually quite an important step. It helps ensure that your fish are healthy and remain that way. Water testing is especially important in a newly set-up aquarium since ammonia and nitrite levels in the water tend to be elevated during the startup cycle in a tank. Keep in mind that water testing isn’t just important for new aquariums, though. In even the most established tanks, the level of harmful substances can increase if the water isn’t changed often enough, filters aren’t cleaned out, the tank is overfull, or medication or other outside factors alter its biological cycle. If you want to keep your fish in the best possible health, you should count on testing your aquarium water about once a week, in addition to any time you notice your fish are getting sick. If you need some guidance to help pick the right water testing kit for your aquarium, here are a few we recommend.

What to Consider in Aquarium Water Testing Kits

Here are a few things to think about before buying an aquarium testing kit:

  • Type: There are quite a few types of aquarium testing kits that measure the levels of different substances. Ammonia, pH, nitrite, nitrate, water hardness, alkalinity, and phosphate are most common parameters that kits will test for. Ammonia, pH, nitrite, and nitrate are the most crucial to test for regularly since too high a level of any of them (or in the case of pH, the level changes too quickly) in your aquarium water can seriously harm or even kill your fish. Water hardness and alkalinity tests aren’t strictly necessary unless you own a special tank, like a planted tank, though measuring them won’t do any harm if they happen to be included in your testing kit. Phosphate tests will be most useful if you’ve had recurring algae problems in your tank. Aquarium water testing kits can also measure chlorine, chloramine, copper, iron, calcium, carbonate hardness, and more.
  • Master vs. Specialty: Keep in mind that no testing kit will let you measure every possible parameter at once. There are quite a few master kits that will allow you to individually check the levels of multiple substances. There are also testing strips that measure for several different parameters at once. Both of these are a handy way to save money in the long run, especially if they come included with a high quantity of tests, though master kits can be time-consuming to use. If you can’t find a master kit or strips that test for a substance you’re concerned about, or you don’t want to measure six or so materials every time you run a test, there are specialty aquarium water testing kits that target only one substance. Kits that measure only ammonia, nitrate, nitrite, phosphate, or just about any harmful substance found in aquarium water can also be purchased, though these individual kits are not generally as cost-effective as master kits. You may prefer them, however, if you don’t want to have to decipher six different test results from one strip when you’re only trying to test your tank’s ammonia levels.
  • Freshwater vs. Saltwater: The kit that’s right for your fish tank will also depend on the type of water in your aquarium. There are testing kits that are meant only for use in freshwater and testing kits meant only for saltwater. Testing kits that are suitable for freshwater and saltwater alike are also an option, depending on what you measure for. Some substances can be tested the same way in both types of aquariums. Others, like pH, require different types of testing kits since saltwater has a naturally higher pH than freshwater. If you opt for a kit that can be used in both types of water, keep in mind that the color-coding system may be different for freshwater than for saltwater and vice versa.

Top Choice: JNW Direct Aquarium Test Strips for Fish Tank

Box of fish tank water testing strips and bottle with levels

A well-equipped aquarium water testing kit that will cover most, if not all, of your needs. It works for freshwater and saltwater tanks (plus outdoor fish ponds, if you have one in your yard) and tests for six parameters. It’ll measure the levels of nitrite, nitrate, free chlorine, water hardness, total alkalinity, and the pH balance of the water. This kit uses aquarium strips to make measurements fast, accurate, and incredibly simple. Dip a strip in the water and then compare the colors on the strip to the color chart on the bottle. You don’t have to do individual tests for each parameter; the results for all six will show up on the strip together. There are 50 strips per bottle, so if you test your aquarium water once a week, this kit will last you almost a year. You also receive a downloadable e-book with your purchase, which explains your test result in more detail and provides tips for keeping your tank water in the healthiest possible condition. As an added bonus, if you have an IOS or Android phone, you’ll also be given access to a free mobile app that will record, track, and monitor your aquarium test strip results and store them on your phone. No longer will you have to set aside a separate journal or notebook to keep track of your water test results.

Top Choice

Aquarium Test Strips - 6-in-1 Aquarium Test Kit with eBook - Aquarium Water Test Kit with Quick and Accurate Fish Tank Test Strips - 50 Test Strips by JNW Direct

An incredibly useful aquarium water testing kit that works in fresh and saltwater, measures six different parameters, and is quick, easy, and accurate.

Best for Freshwater: API Freshwater Aquarium Water Test Kit

freshwater aquarium testing kit in a carrying bin

If you own a freshwater aquarium, this highly trusted master testing kit is an excellent choice for both regular weekly testing or when seemingly invisible problems with your water or fish pop up. Designed only for freshwater tanks, this kit is designed to monitor and measure the most important parameters to test for weekly, ammonia, nitrite, nitrate, and pH balance and high range pH, which are also worth keeping an eye on in freshwater aquariums. Testing is both quick and accurate. The entire kit is comprised of seven bottles of testing solution, a color chart, four glass test tubes with caps, and easy-to-follow instructions. The contents of each bottle test for a different substance, so keep in mind that you will have to run five separate tests to measure the levels of each parameter. Since it only takes a few drops from the bottles to run the tests, you’ll be able to run more than 800 tests with these kits, keeping you well-supplied for an extended period of time even if you take measurements every week.

Best for Saltwater: API Saltwater Aquarium Water Test Kit

saltwater aquarium testing kit in a carrying bin

If you want a specialty test for your saltwater home aquarium, this easy-to-read testing kit will be right up your alley. Specifically designed for use in saltwater, this test is both fast and accurate and tests for the most crucial parameters to keep an eye on your tank. You can individually test aquarium water for high range pH, ammonia, nitrite, and nitrate. The included instructional booklet contains directions to guide you through the individual testing process for each parameter. The kit also contains six bottles of testing solution, a laminated and scientifically accurate color chart, four test tubes, a holding tray for the solutions, and a test tube rack for more convenient testing. And with the potential to run more than 550 tests per kit, it’ll last you a good long while, even with recommended weekly testings. If you own a reef aquarium, there is a separate testing kit specifically meant for reefs.

Best for Saltwater

API SALTWATER MASTER TEST KIT 550-Test Saltwater Aquarium Water Test Kit

An easy-to-read master aquarium water testing kit designed to measure key parameters in saltwater tanks.

Best for Budget: Tetra 6-in-1 Aquarium Test Strips

packet of aquarium water testing strips

Weekly testing of your aquarium water can be a pricey endeavor since you’ll need to constantly refresh your supply of testing kits or strips. But if you want to ensure your tank water and fish are as healthy as possible, you can’t skimp on regular testing. These aquarium water testing strips offer a cost-efficient and effective solution to this problem. For one low price, you receive either a set of 25 or 100 test strips, enough to last you half a year or over a year (assuming you only test weekly) before you need to buy new ones. Each strip is able to measure up six different parameters in one: Nitrates, nitrites, water hardness, chlorine, alkalinity, and pH levels. And they’re extremely quick and convenient to use besides. All you have to do is dip the strip into the water, wait 60 seconds, and compare the results to the scale on the bottle. Instructions and when it’s recommended to test your aquarium water (beyond weekly testing) are located on the back of the packet if you ever need some guidance. And don’t worry about whether you have a freshwater or saltwater aquarium or what life stage your tank is at; these versatile strips will work on them all.

Best for Budget

Tetra EasyStrips 6-In-1 aquarium Test Strips, Water Testing (19542)

Versatile and affordable aquarium water testing strips that give you your results within 60 seconds of testing.

Also Great: BOSIKE Aquarium Test Strips

aquarium water testing strip with yellow, white, and blue markings next to its bottle and box

This six-in-one testing kit is suitable for a wide number of different aquariums and tanks. Whether you keep tropical fish or shrimp, a betta tank, or an outdoor pond, these widely applicable strips will be able to test the water in them all. They measure for water hardness, nitrate, nitrite, Cl2, carbonate, and pH balance all at once. There’s also an ammonia testing-only version of these strips if you’re ever concerned about its levels in your tank. With 125 strips per bottle, you have plenty of tests to keep you well-supplied for regular testing intervals, whether once or twice a week. They work incredibly fast, even by aquarium water testing strip standards. Dip one testing strip into your aquarium water for two seconds, remove it, hold it horizontally for 60 seconds, and then compare with the color chart on the bottle. Each strip is made from high-quality fiber paper and the colors are non-bleeding, so you won’t have to worry about them running together when they get wet.

Also Great

BOSIKE 6 in 1 Aquarium Test Strips Kit - 125 Fresh Water Fish Tank Tester Strips for Total Hardness, Nitrate, Nitrite, Cl2, Carbonate & ph Testing

Widely applicable aquarium water testing strips that work in a wide variety of fresh and saltwater tanks and ponds.

Meghan Herlihy Meghan Herlihy
Meghan Herlihy is a full-time writer for LifeSavvy and How-To Geek and has written across a wide variety of topics, genres, and formats, including radio talk shows, local sports journalism, and creative original fiction. She received her bachelor's degree in communications from Ithaca College and a master's in writing from Johns Hopkins University. When she's not writing, you're most likely to find her reading a book, petting every dog within eyesight, and indulging in her love of travel. Read Full Bio »
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