The 10 Best Aquarium Water Test Kits of 2022

Our favorite aquarium test kit is the API Master Test Kit

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Mother and baby son looking at aquarium
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Maintaining good water quality is an essential component of keeping an aquarium. A great tool to help you keep track of your tank’s water is an aquarium test kit. These helpful kits give you physical numbers for your nitrogen cycle, pH, KH, GH, oxygen, and temperature so you can get a better idea of the unseen health of your tank. And keeping track of these numbers could mean the difference between having a thriving aquatic community with fish and live plants or coral and one that is deadly to your aquatic friends.

When shopping for aquarium test kits, there are two things that you need to keep in mind: the output range and the instructions. The former can varies by what type of tank you have—saltwater or freshwater—while the latter will make it easier for you to properly conduct the test, so you know you’re getting accurate results. To help you find the best aquarium test kits for your tank, we researched various options with these considerations in mind.

Our top pick is the API Freshwater Master Test Kit because it’s affordable, readily available, tests various parameters, and has clear instructions and a high output range ideal for freshwater tanks.

Read on to discover the best aquarium test kits to keep your water in tip-top shape.

Our Top Picks

Best Overall

API Freshwater Master Test Kit

API Freshwater Master Test Kit

Chewy

What We Like
  • Easy to use

  • Affordable

  • Readily available

  • Very comprehensive

What We Don't Like
  • Must follow directions closely

  • No place to safely store glass vials

Readily available in most major pet stores, the API Freshwater Master Test Kit has a great price point and reliable results. It includes four glass test tubes with snap-tight caps and over 800 tests that check for pH, high range pH, ammonia, nitrite, and nitrate. Since it has various testing parameters, it’s a great option for weekly maintenance. However, the brand says you can use it whenever you begin to notice fish or water problems. You can use the tub it comes in as a storage case, but note that there isn’t a place inside to store the glass vials upright, so you may want to buy a stand to reduce the risk of breaking them.

Meanwhile, the instructions are very easy to follow, however, it is critical that you read them carefully. The nitrate test, in particular, is known for being tricky to perform correctly. We recommend shaking all of your reagents thoroughly before testing. Some of the ranges are a little broad, but they will still provide essential information. In order to best read the color gradients, it is recommended to bring your vials out into bright light and hold a white piece of paper behind them.

Price at time of publish: $27

Testing Parameters: Ammonia, nitrite, nitrate and high and low range pH

Best Saltwater Test Kit

Salifert Master Reef Testing Combo Kit

Salifert Master Reef Testing Combo Kit

Amazon

What We Like
  • Easy to use

  • Great for coral tanks

  • Very comprehensive

What We Don't Like
  • Can be tricky to read results

  • Expensive

Saltwater tanks are typically fussier about their water quality levels, and the Salifert Master Reef Testing Combo Kit contains all the elements you need to keep an eye on things. A bit more expensive than other test kits on the market, this combo includes 50 to 100 calcium tests, 100 to 200 carbonate alkalinity tests, 60 phosphate tests, 50 magnesium tests, 60 nitrate tests, and 50 pH tests. Calcium, magnesium, phosphate, and carbonate alkalinity tests are especially important for monitoring corals. The tools you’ll find in each kit vary between syringes, spoons, testing vials, plastic tips, and a chart to find your reading.

The instructions for each kit are easy to follow, and you can use the box they come in as a storage box so you don’t lose any pieces. Some of the tests—particularly, the nitrate—have broad output ranges, so make sure you’re following the directions very carefully. Make sure you read your results in a well-lit area (preferably in bright light with a white background) for the greatest accuracy.

Price at time of publish: $93

Testing Parameters: Calcium, carbonate alkalinity, phosphate, magnesium, nitrate and pH

Best Ammonia Test

API Ammonia Test Kit

API TEST KIT

Amazon

What We Like
  • Inexpensive

  • Readily available

  • Advises how to correct tank issues

  • Low reference ranges on color cards

What We Don't Like
  • Can be tricky to read results

  • Can’t differentiate between ammonia and ammonium

If you are looking to test your ammonia—a couple of examples of this would be if you are doing a fishless cycle or adding new live critters to your tank—then the API Ammonia Test Kit is the best choice. It includes two testing solutions with child-resistant capped bottles, one test tube with a snap-tight cap, two color cards to compare your results, and easy-to-read instructions. We also appreciate that the instructions advise how to correct your water should your results be unfavorable.

The test measures between 0 and 8 ppm and has the lowest reference range available on the commercial market between 0 mg/L, 0.25 mg/L, and 0.5 mg/L on the included color chart, so it provides the most helpful information. Some may find it hard to distinguish between the result colors, so we recommend holding your vial in direct sunlight with a white background for an accurate reading. Overall, this is a very affordable test that is easily found in local and online pet stores.

Price at time of publish: $14

Testing Parameters: Ammonia

Best Nitrite Test Kit

Monitor Nitrite Test Kit

Monitor Nitrite Test Kit
What We Like
  • Wide test range

  • Inexpensive

  • Comes with an instructional video

What We Don't Like
  • Limited availability

  • Can be tricky to read results

Nitrite, the middle of your nitrogen cycle, is often overlooked once your system has been established. But if your ammonia or nitrate are fluctuating, it is critical that you also evaluate your nitrite levels to see where all of your nitrogen products are registering. To best test your nitrite levels, we recommend the Monitor Nitrite Test Kit. This test kit has a better range of values and can detect lower levels of nitrite than other test kits on the market. It comes with enough tools and materials to perform 200 tests, and it can work for both freshwater and saltwater aquariums.

However, what we really love about this kit is that the brand offers an instructional video, so it’s easy for users to understand and use. It also comes with a color card to help you determine your results. Like other options on this list, the color cards can be hard to differentiate. View your results in bright light and on a white background. We also love that this test is very inexpensive, however, it’s not as readily available as other options, so keep that in mind when purchasing.

Price at time of publish: $10

Testing Parameters: Nitrite

Best Nitrate Test Kit

Salifert Nitrate Test Kit

Salifert Nitrate Test Kit

Amazon

What We Like
  • Wide test range

  • Easy to use

  • Inexpensive

What We Don't Like
  • Can be tricky to read results

  • Unclear if safe for freshwater and saltwater

Nitrate, the end product of your nitrogen cycle, can be a big issue in freshwater and marine tanks. At low levels, nitrate is usually safe for your fish, but high levels can harm your fish. Ensuring low nitrate is often an overlooked component of maintaining an aquarium, and most test kits for nitrate have a wide range that can be difficult to read, but the Salifert Nitrate Test Kit is the exception. We recommended it for its high and low range test and easy-to-use setup. It comes with a syringe, testing vial, scooper, and nitrate solutions to test your water. The entire kit can perform up to 60 tests and should work efficiently in saltwater and freshwater aquariums. However, note that some retailers advertise it as being safe for only freshwater or only saltwater.

To use it, collect a sample of your aquarium water and then follow the kit’s directions carefully. Overall, the instructions are easy to read and follow, and you can compare your results to the provided color chart. As always, we recommend viewing your results against the color chart in bright light and on a white background for the most accurate comparison.

Price at time of publish: $15

Testing Parameters: Nitrate

Best pH Test Kit

API pH Test Kit

API pH Test Kit

Amazon

What We Like
  • Easy to use

  • Easy to read

  • Inexpensive

What We Don't Like
  • Small output range

  • Not for saltwater aquariums

Water pH is an essential component of your aquarium’s water quality and influences all living animals in your system. For testing pH, you can use a liquid test kit or an electronic probe. Electronic probes can be more accurate if calibrated properly but are more expensive than their liquid counterparts. Due to this, we recommend using the API pH Test Kit. It comes with a testing vial, testing solution, color card, and a glass vial with a snap-tight cap to prevent messes. The entire kit can be used for around 250 tests and accurately tests pH within a 6.0 to 7.6 range. This is ideal for freshwater tanks, so if you have a saltwater tank (or a freshwater tank with a higher optimal pH range), you will need to look for another product, like the API High Range pH Test Kit.

With liquid test kits, it is essential that you read the instructions carefully and keep your reagents fresh. To use it, gather a 5-milliliter water sample of your water into the clean testing tube. Then add three drops of the testing solution, holding the bottle completely vertical. Afterward, cap the vial and invert it a few times to mix the water and solution. Finally, compare the color to the color card and write down your results. Like with any color chart, we recommend reading your results in a well-lit area on a white background.

Price at time of publish: $8

Testing Parameters: pH range of 6.0 to 7.6

Best KH/GH Test Kit

API GH & KH Test Kit

API GH & KH Test Kit

Walmart

What We Like
  • Two tests in one

  • Inexpensive

  • Easy to use

  • Readily available

What We Don't Like
  • Have to convert results

  • No set number of tests per kit

Your aquarium’s carbonate alkalinity (KH) and total hardness (GH) are both critical components to your tank’s health and are often overlooked. The API GH & KH Test kit is a highly recommended addition to any test kit setup being easy to use, cheap, and readily available. Like other API tests, it comes with everything you need, including two testing solutions, two vials, easy-to-read instructions, and a glass vial with childproof safety caps. However, this test kit does not have a certain amount of tests per kit because the number of drops you use per water sample will vary. Make sure you follow the specific directions carefully and read your results in a well-lit area on a white background for accuracy.

The biggest complaint with this system is that it measures KH and GH in dKH and dGH, which can be confusing to interpret. By multiplying your drop results by 17.1 mg/L, you will have a number in ppm, which is an easier metric to wrap your mind around. It’s also advertised as freshwater only, but the output ranges are wide enough to cover saltwater and brackish aquarium water.

Price at time of publish: $11

Testing Parameters: General hardness and carbonate hardness

Best Oxygen Test Kit

Salifert Oxygen Test Kit

Oxygen Test Kit
What We Like
  • Wide test range

  • Inexpensive

  • Quick results

What We Don't Like
  • Can be tricky to read results

  • Must follow directions closely

Oxygen levels are critical for your live fish and invertebrates and can be easily tested by an electronic probe or test kit. While probes may have more accuracy, they are more expensive and require regular calibration. That’s why we love the Salifery Oxygen Test as a budget-friendly alternative. It comes with three testing solutions, a testing vial, a syringe, and a color card. There’s enough for 40 tests, and it can be used in freshwater, saltwater, and pond water tanks. The included instructions are easy to read and follow, but it’s imperative that you follow them closely to ensure that you perform the test properly. This is especially important when you add the drops of the testing solutions to your water sample since the directions emphasize not shaking the vial. Once you’ve completed the steps, review your results in bright light on a white background for accuracy.

Since it can test for 2 to 14 mg/L, it’s a great option for looking at lower oxygen levels, which can happen as tank temperatures warm or equipment is being swapped out. While it may seem like a lower-range test kit, even if you maxout the test, your levels are still safe. Overall, this is a reliable option that’s readily available in many local pet stores and online retailers.

Price at time of publish: $15

Testing Parameters: Oxygen

Best Phosphate Test Kit

Red Sea Phosphate Pro Test Kit

Red Sea Phosphate Pro Test Kit

Amazon

What We Like
  • Wide test range

  • Comes with storage case

  • Easy to use

What We Don't Like
  • Expensive

  • Bottles can leak

If you have corals growing in your tank, it is imperative to track phosphate levels, which can possibly inhibit their growth and cause serious algae overgrowth. To test for these levels in your aquarium, we recommend using the Red Sea Phosphate Pro Reef Test Kit. It comes with two testing solutions, a syringe, a colorimetric wheel, and two glass vials to complete up to 100 tests. However, what really makes this option stand out is the included vial stand and a durable plastic storage case that can house the whole kit. Make sure the testing solutions are closed securely when you store them since they tend to leak, which could ruin the other supplies provided in the kit.

Meanwhile, the instructions are very easy to read and follow, just be sure to review your results in good lighting and on a white background for accuracy. Since it has low- and high-range testing, this is an excellent option for saltwater reefs. Although it’s pricier than other options, we recommend this kit due to its reliability and accuracy.

Price at time of publish: $39

Testing Parameters: Phosphate

Best Copper Test Kit

API Copper Test Kit

API Copper Test Kit

Amazon

What We Like
  • Wide test range

  • Easy to use

  • Advises how to correct tank issues

What We Don't Like
  • Can be tricky to read results

Whether you’re treating your system for parasites, have an outdoor system, or have old copper pipes, monitoring your copper level is critical to ensuring the health of your fish. At low levels, copper can be harmful and cause secondary illness in fish due to the weakening of the immune system. To test copper, we recommend using the API Copper Test kit because it’s inexpensive and can be used in freshwater, tap, and saltwater aquariums. Each kit comes with a bottle of testing solution, color chart, and vial with a snap-tight cap to prevent messes and can last for up to 90 tests. It’s effective enough for weekly testing, when problems appear, or when medicating. We always recommend testing your KH before you treat it with copper to ensure your copper levels will not hurt your fish.

The test can detect copper levels between 0 to 4 ppm, so it’s suitable to detect trace amounts to higher concentrations. To use the kit, simply collect your water, add the drops as specified in the instructions, mix it, and then compare your results to the color card in a well-lit area. When comparing your results, make sure you remove the cap and look down from the test tube from above for the most accurate reading. Fortunately, the kit also includes information on how to treat your water if the results come back unfavorable.

Price at time of publish: $12

Testing Parameters: Copper

Final Verdict

Ensuring good water chemistry in your aquarium is essential to fish health and wellbeing, and having a reliable and accurate test kit makes a difference. For a master test kit, we recommend the API Freshwater Master Test Kit for freshwater tanks and the Salifert Master Reef Testing Combo Kit for saltwater tanks. Both kits contain multiple tests to measure everything from pH to nitrate to nitrite and more to keep your water clean and healthy for your aquatic environment.

What to Look For in Aquarium Test Kits

What Is Tested

There are many different chemical components of the aquarium water that potentially can be tested, but for most people, a water test kit that covers the basics is sufficient. At a minimum, your kit should test for:

  • Water pH
  • Ammonia
  • Nitrite
  • Nitrate

If you want to go further, there are test kits that also evaluate water hardness, copper, iron, phosphate, and other water chemistries, but these extra tests might be more complication than you need.

Output Ranges

When considering a test kit, make sure it gives results that are appropriate for your system. Nitrate levels, for instance, should test at very low levels in saltwater tanks, whereas some freshwater systems can have higher levels. Testing for low levels of nitrate would be appropriate for one system and not as critical for the other.

Clear Usage Instructions

Depending on which product you select, always read the instructions carefully prior to using them. You’ll want to follow each step exactly to provide the most accurate result. If the instructions indicate shaking the reagents for a certain amount of time, do not skip this step. This is critical to proper test kit function.

FAQ
  • How often should I test my water?

    With established systems, you should test your water quality at least once a month, but more frequently is always fine, too. New systems less than 4 to 6 weeks old should be tested daily in order to ensure your New Tank Syndrome is not getting out of hand. Systems with newly incorporated live components, such as fish, invertebrates, and live rock, or new equipment, such as pumps and filters, should be tested at least once a week. Finally, always write your values down (do not expect to remember everything from your last test).

  • How long is my test kit good for?

    Once you have opened your reagents, you have one year to use your test kit. If you store it outside, you will only have six months. Yes, these test kits have expiration dates on the side, but that’s for stores to know when they have been sitting on the shelves too long. Once you crack into your test kit, write the date on the side and toss it one year later.

  • Which parameters should I test for my freshwater tank?

    In freshwater systems, you should always test your nitrogen cycle (ammonia, nitrite, and nitrate), pH, KH, GH, and temperature. If you have live plants and are adding iron or carbon dioxide, you may need to test for these as well. Oxygen testing is not frequently required unless you have a larger system with significant temperature fluctuations.

  • Which parameters should I test for my saltwater tank?

    Fish-only saltwater tanks should test your nitrogen cycle (ammonia, nitrite, and nitrate), pH, KH, GH, and temperature, just like freshwater systems. If you have corals, you will need to test your phosphate, calcium, magnesium, and other trace elements, depending on which species of coral you are working with.

  • Why can’t I use test strips?

    Test strips are a complete waste of money since they do not give reliable information. Our office independently tested three brands with three brand new containers and three water sources. All the strips came out with a range of data right out of the box. While it takes a little extra effort to use a liquid-based test kit, it is well worth the effort since they provide reliable information.

Why Trust The Spruce Pets?

With 10 years of practicing as an aquatic veterinarian, Dr. Jessie Sanders always discusses water quality with her clients and recommends that they test their parameters on their own. She has personal experience with all of the above brands and has conducted her own comparison tests back when she worked at an aquatics-only veterinary hospital. She says she knows these colorimetric charts are hard to read, so it takes some practice with the correct lighting to get a good handle on reading these test kits.

Article Sources
The Spruce Pets uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Aquarium water quality: Nitrogen cycle. Florida Department of Agriculture and Consumer Services

  2. Wang Lu et al. Corals and their microbiomes are differentially affected by exposure to elevated nutrients and a natural thermal anomaly. Frontiers in Marine Science, vol. 5. 2018. doi:10.3389/fmars.2018.00101

  3. Wang T, Wen X, Hu Y, Zhang X, Wang D, Yin S. Copper nanoparticles induced oxidation stress, cell apoptosis and immune response in the liver of juvenile Takifugu fasciatusFish Shellfish Immunol. 2019;84:648-655. doi:10.1016/j.fsi.2018.10.053

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