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The 15 Best Aquarium Water Test Kits

It's important to your aquarium's health that you keep the water clean and clear. Aquarium test kits are useful for monitoring the water in your tank.

You can gain insight into your tank's potential health with the help of these kits, which provide tangible measurements of the nitrogen cycle, pH, KH, GH, oxygen, and temperature.

Monitoring these parameters is very important if you want to ensure the health of the fish, plants, and corals in your aquarium.

When looking for aquarium test kits, it's important to consider both the output range and the instructions that come with them.

The former method may vary based on whether you are testing in a saltwater or freshwater tank, while the latter will help you perform your testing more efficiently, ensuring reliable results.

We've reviewed many options with these factors in mind to help you choose the best aquarium test kit for your tank.

The API Freshwater Master Test Kit is our top pick because it's perfect for freshwater aquariums, has a wide output range, is easy to use, and is reasonably priced.

Keep your aquarium water in pristine condition BestForPets (bestporpets.org) has come up with the help of the best aquarium water test kits you can find below.


Top Pick: API Freshwater Master Test Kit

The API Freshwater Master Test Kit, found at a reasonable price at most large pet stores, provides accurate readings.

It has over 800 tests that measure pH, high range pH, ammonia, nitrite, and nitrate, and it comes with four glass test tubes with snap-tight covers. It’s ideal as a weekly choice for upkeep due to its flexible testing conditions.

However, the manufacturer recommends using it as soon as any fish or water concerns are noticed. Keep in mind that there is nowhere in the tub for the glass vials to stand, so you may want to invest in a separate stand if you’re concerned about breakage.

On the other hand, the directions are brief and straightforward; however, you should read them well. Particularly challenging is the nitrate test.

Before doing any tests, give your reagents a good shake. The ranges are quite vague in places, but they will still give helpful context. Bring your vials out into bright light and hold a white piece of paper behind them to better read the color gradients.

Ammonia, nitrite, nitrate, and pH in the high and low ranges are the test parameters.

Enjoyments of Ours

  • Simply put, it’s a breeze to use
  • Affordable
  • In a moment’s notice
  • Very exhaustive

We Dislike

  • Must pay attentive attention to instructions
  • Having nowhere to put glass vials


Salifert Master Reef Testing Combo Kit is the best saltwater test kit

The Salifert Master Reef Testing Combo Kit has everything you need to maintain tabs on your saltwater aquarium’s water quality, which is more finicky than regular aquarium water.

This package 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, and it is a bit more expensive than other test kits on the market.

Coral health monitoring relies heavily on calcium, magnesium, phosphate, and carbonate alkalinity testing. There are a wide variety of syringes, spoons, testing vials, plastic tips, and a chart to help you interpret your results included with these kits.

Each kit has straightforward instructions, and the packaging can be kept for future reference. Take special care to follow the provided instructions for any tests that need a specific input value, such as the nitrate test, as the possible output values span a wide spectrum.

If you want the most precise findings, you should read them in a well-lit room (ideally with bright light and a white backdrop).

Calcium, carbonate alkalinity, phosphate, magnesium, nitrate, and pH are some of the test parameters.

Enjoyments of Ours

  • Simply put, it’s a breeze to use
  • Especially useful for reef aquariums.
  • Very exhaustive

We Dislike

  • Results may be difficult to interpret.
  • Expensive


Using an API Ammonia Test Kit is the Preferred Method

The API Ammonia Test Kit is the ideal option if you want to check your ammonia levels, which you may want to do before adding any additional live animals to your tank or during a fishless cycle.

You’ll get two testing solutions in child-proof bottles, a test tube with a secure lid, two comparison cards in different colors, and clear directions.

It’s helpful that the instructions include tips for improving the water quality in case the test turns up negative findings.

With a reference range of 0 mg/L, 0.25 mg/L, and 0.5 mg/L on the supplied color chart, this test is superior than others on the market. It measures concentrations from 0 to 8 ppm.

We recommend reading your vial in direct sunshine against a white backdrop since some people may have trouble seeing the different colors of results apart.

Generally speaking, this is a cheap test that can be purchased from any number of brick-and-mortar or virtual pet supply outlets.

Ammonia Levels as a Measuring Stick

Enjoyments of Ours

  • Inexpensive
  • In a moment’s notice
  • Provides recommendations for fixing tank problems
  • Color cards with limited ranges of validity

We Dislike

  • Results may be difficult to interpret.
  • Mistakes ammonia for ammonium


The Nitrite Test Kit from ELISA Monitor is the Best Option

Once a system is up and running, nitrite, the nitrogen cycle’s midpoint, is generally disregarded. However, if your ammonia or nitrate levels are changing, you must also check your nitrite levels to get the overall nitrogen product reading.

We advise using the Monitor Nitrite Test Kit to check your nitrite levels. When compared to similar kits on the market, this one has a wider range of readings and can detect lower amounts of nitrite.

It may be used in either freshwater or saltwater aquariums, and it comes with enough supplies for 200 tests.

But the thing that really sold us on this set was the fact that the manufacturer included a video tutorial to make everything crystal clear. Included is a color card to help in interpreting the results.

The color cards, like some of the other choices here, can be difficult to tell apart at a glance. Examine the data while sitting in front of a white background and lots of light. We really appreciate how cheap this test is; but, it’s not as widely available as some other choices.

Nitrite Measurements

Enjoyments of Ours

  • Range of possible outcomes
  • Inexpensive
  • With a video guide included.

We Dislike

  • Scarce resources
  • Results may be difficult to interpret.


Nitrate testing kits, the Salifert Nitrate Test Kit is the best option

The nitrogen cycle’s waste product, nitrate, can cause severe problems in both freshwater and saltwater aquariums. Nitrate is generally healthy for your fish at low concentrations, but at large concentrations, it can be harmful.

1 Most nitrate test kits have a broad range that can be difficult to read, but the Salifert Nitrate Test Kit is an exception. Ensuring low nitrate is an often-overlooked part of aquarium maintenance.

We vouch for its user-friendliness and the fact that it can test both high and low frequencies. Kit includes a syringe, test vial, scooper, and nitrate solutions for water analysis.

As a whole, the kit is capable of 60 separate tests, and it should function adequately in both saltwater and freshwater tanks. Some stores may label it as suitable for either fresh or salt water, so be aware.

Take a water sample from your aquarium and follow the kit’s instructions to utilize it. The directions are straightforward, and there’s even a handy color chart to help you evaluate your progress.

Always check your work against the color chart in good lighting and on a white backdrop to get the most accurate impression.

Measurements for Nitrate

Enjoyments of Ours

  • Range of possible outcomes
  • Simply put, it’s a breeze to use
  • Inexpensive

We Dislike

  • Results may be difficult to interpret.
  • It’s unclear whether it’s safe for both saltwater and freshwater use.


Most Accurate pH Test Kit: API pH Test Kit

The pH of the water in your aquarium is a crucial indicator of the overall health of the ecosystem you’ve created. Either a liquid test kit or an electronic probe can be used to determine the pH level.

While electronic probes may be more precise than their liquid equivalents, adequate calibration might increase their price. This is why the API pH Test Kit comes highly recommended.

A glass vial with a snap-tight top prevents spills, and there is also a testing vial and testing solution, as well as a color card. The pH testing kit provides reliable readings between the ranges of 6.0 and 7.6 and may be used for about 250 separate tests.

If you have a saltwater tank (or a freshwater tank with a larger optimum pH range), you’ll need to look elsewhere, maybe at the API High Range pH Test Kit.

The directions and reagents in liquid test kits must be followed precisely for accurate results. To use, just collect a 5-milliliter sample of your water and place it in the sterile testing tube provided.

Then, while holding the bottle upright, add three drops of the test solution. After that, put the top back on the vial and turn it upside down several times to ensure the water and solution are thoroughly combined.

Finally, record your findings after comparing the color to a standard color card. We advise reading your findings in a well-lit room against a white background, as you would with any color chart.

pH values between 6.0 and 7.6 are used as test parameters.

Enjoyments of Ours

  • Simply put, it’s a breeze to use
  • Very readable
  • Inexpensive

We Dislike

  • Tight variation in output
  • No good for marine tanks with saltwater


The API GH & KH Test Kit is the Most Accurate KH/GH Kit Available

Total hardness (GH) and carbonate alkalinity (KH) are two often-overlooked yet crucial parameters for a healthy aquarium. Because it is simple, inexpensive, and widely available, the API GH & KH Test kit is a great addition to any testing arsenal.

A glass vial with a childproof safety top and two testing solutions are included, as are straightforward instructions and everything else you’ll need to conduct the test.

The number of tests you can do with this kit is not fixed, however, because the amount of drops used to analyze a given water sample may vary. Make sure you read the findings in a well-lit room against a white background to ensure accuracy, then do what the instructions say.

The most problematic aspect of this technique is that KH and GH are measured in misleading derivative forms (dKH and dGH).

To convert from milligrams per liter to parts per million (ppm), just multiply your drop result by 17.1 mg/L. Though it’s marketed as being for freshwater only, its output settings are flexible enough to accommodate salty and brackish aquarium water.

General hardness and carbonate hardness are the parameters for the tests.

Enjoyments of Ours

  • Like taking two exams at once
  • Inexpensive
  • Simply put, it’s a breeze to use
  • In a moment’s notice

We Dislike

  • The data must be converted.
  • There is no fixed amount of tests that come in a package.


Salifert’s Oxygen Test Kit is the Gold Standard

A simple electronic probe or test kit will tell you whether or not the oxygen levels in your aquarium are safe for your fish and invertebrates. Although probes might potentially provide more accurate results, they are also more costly and need to be calibrated frequently.

To that purpose, we recommend the less expensive Salifery Oxygen Test. Three test solutions, a syringe, a vial, and a color chart are included. There’s enough for 40 tests, and it’s suitable for both saltwater and freshwater aquariums as well as ponds.

The accompanying instructions are clear and straightforward, but strict adherence is required for a reliable result. The instructions stress the need of not shaking the vial while adding the drops of testing solutions to your water sample.

When you are finished, double-check your work in good lighting against a white background to ensure accuracy.

Lower oxygen levels can occur as tank temperatures raise or equipment is switched out, and this test’s range of 2 to 14 mg/L makes it a suitable choice for investigating these occurrences.

Despite the kit’s seeming limited capabilities, even at the test’s upper limit, your exposure is far within acceptable parameters. Overall, it’s a solid choice that can be found in many brick-and-mortar and virtual pet supply shops.

Oxygen Levels as a Measuring Stick

Enjoyments of Ours

  • Range of possible outcomes
  • Inexpensive
  • Immediately Observable Outcomes

We Dislike

  • Results may be difficult to interpret.
  • Must pay attentive attention to instructions


Red Sea Phosphate Pro Test Kit Is The Top Choice For Phosphate Analysis

Keep an eye on your phosphate levels if you have corals in your tank, since high concentrations can stunt coral growth and lead to an algae bloom.

2 We advise utilizing the Red Sea Phosphate Pro Reef Test Kit to check these parameters in your aquarium. Everything you need to conduct up to a hundred tests—including two testing solutions, a syringe, a colorimetric wheel, and two glass vials—is included in the kit.

Vial stand and hard plastic case are what set this choice apart from the rest, though. If you plan on storing the testing solutions, make sure the lids are tight so no leaks destroy the other materials in the kit.

The directions are straightforward, and all you need to do to get accurate results is look at them against a white background and in excellent lighting.

This is a great choice for saltwater reefs because it can test at both low and high levels. This kit is more expensive than several alternatives, but it is the most reliable and accurate choice.

Phosphate Values as a Measuring Stick

Enjoyments of Ours

  • Range of possible outcomes
  • Accessories include a convenient carrying bag
  • Simply put, it’s a breeze to use

We Dislike

  • Expensive
  • This is a common problem with bottles.


Copper Test Kit: API Copper Test Kit

It’s important to keep an eye on your copper level if you’re using parasite treatments, have an outdoor system, or have ancient copper pipes, all of which might have a negative impact on your fish.

Copper, even at low concentrations, can be toxic to fish and lead to secondary sickness by suppressing the immune system. 3 Due to its low price and versatility (it may be used in freshwater, tap water, or saltwater aquariums), we advise utilizing the API Copper Test kit for this purpose.

With the included vial, color chart, and spill-proof closure, each kit may accommodate up to ninety tests. It’s reliable enough to use weekly, in the event of complications, or while administering medication.

It is imperative that you test your KH before applying any copper treatment to guarantee the safety of your fish.

The test is sensitive enough to identify tiny quantities of copper and can also handle greater concentrations (up to 4 ppm).

Gather some water, add the drops in the prescribed order, stir, and then check the results against the color card under good lighting.

Take off the top of the test tube and peer down into it from above to get the clearest comparison readings. If the findings of your water test come back unfavorable, the kit will also instruct you on how to remediate the water.

Copper Test Parameters

Enjoyments of Ours

  • Range of possible outcomes
  • Simply put, it’s a breeze to use
  • Provides recommendations for fixing tank problems

We Dislike

  • Results may be difficult to interpret.

Aquarium Checklist: What to Look For

Power levels

In deciding on a test kit, it is important to make sure that the findings are reliable and accurate for your setup.

To provide one example, nitrate levels in saltwater tanks should be rather low, but in freshwater systems they can be greater. Nitrate testing is essential for one system but not as important for another.

Explicit directions for use

No matter what product you buy, you should always follow the directions to the letter before using it. If you want a precise outcome, you need to follow the instructions to the letter.

Don’t forget to shake the reagents for as long as the directions say to. This is a must for every functioning test kit.

When should I take a water sample?

Once a month is the very minimum for testing water quality in established systems; more frequent testing is OK. Every day testing is necessary to prevent New Tank Syndrome from getting out of hand in systems that are less than 4 to 6 weeks old.

At the very least, you should check your system once a week, especially if you’ve just added any living components like fish, invertebrates, or live rock, or any new equipment like pumps or filters.

Never forget to record your beliefs and principles (do not expect to remember everything from your last test).

When does my test kit expire?

The shelf life of an unopened test kit is indefinite, however once the reagents have been opened, you have one year to utilize them. Just six months if you keep it in the open air.

These test kits, like many others, have use-by dates on the packaging to alert retailers to when they’ve been on the market for too long. Mark the day you opened the kit on the side and throw it away when a year has passed.

What should I look for while testing my freshwater aquarium?

Always check the pH, KH, GH, and temperature of your freshwater system, as well as the nitrogen cycle (ammonia, nitrite, and nitrate).

If you are working with living plants and want to supplement them with iron or carbon dioxide, you may also wish to do appropriate tests.

Unless you have a really big system or one that experiences extreme temperature changes, oxygen testing is usually not necessary.

When checking my saltwater aquarium, which factors should I look for?

For both freshwater and saltwater aquariums, it’s important to regularly check the nitrogen cycle (ammonia, nitrite, and nitrate), pH, KH, GH, and temperature.

Depending on the coral species you’re dealing with, you may need to check levels of phosphate, calcium, magnesium, and other trace elements in your aquarium.

I don’t see why test strips are off limits.

There is no use in spending money on test strips because they do not provide accurate results. Three different brands were put through their paces by our staff using three different fresh containers and three different supplies of water.

Out of the box, each strip included a variety of readings. The additional time and effort required to utilize a liquid-based test kit is justified by the accuracy of the results.


The health and well-being of your fish depends on the quality of the water in your aquarium, which can be tested using the best aquarium water test kits and most reliable test kits.

BestForPets (bestporpets.org) recommends the API Freshwater Master Test Kit for freshwater aquariums and the Salifert Reef Test Combo Kit for saltwater aquariums as the best master test suites on the market.

Both kits have a number of tests for things like pH, nitrate, nitrite, and more that can help you keep the water in your aquatic environment clean and healthy. 

Author Image

Dr. Deborah Fletcher

Deborah R. Fletcher, DVM, is a skilled veterinarian with more than 15 years of experience dealing with companion and exotic animals. She has experience caring for a variety of animals, including household cats and dogs, reptiles, birds of prey, and even primates. Dr. Fletcher is a valuable part of the BestForPets team, where she contributes to their aim of providing pets and their owners with the finest possible treatment and services.

Veterinarian (DVM) Dr. Deborah Fletcher


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