An aquarium tank requires regular maintenance. This isn’t merely a matter of filling it and letting it do its thing. Regular water changes help ensure that harmful levels of ammonia and nitrites don’t build up to unsafe concentrations. However, sometimes things can go wrong without much warning.

That’s where testing the water comes into play.

Many fish have narrow ranges for acceptable levels of pH, hardness, and other elements of water chemistry. That’s why it’s essential to monitor them in order to avoid sudden changes that could stress out your fish. Our guide covers everything that you need to know about what you should test for and why it’s essential. We’ve also included reviews of some of the best products to get you started.

Let’s dive in!divider3 goldfish bowl

A Quick Comparison of Our Favorites

Image Product Details
Best Overall
Winner
API 5 in 1 Freshwater & Saltwater Aquarium Test Strips API 5 in 1 Freshwater & Saltwater Aquarium Test Strips
  • Convenient
  • Narrow pH window
  • Affordably priced
  • Best Value
    Second place
    API Freshwater Aquarium Master Test Kit API Freshwater Aquarium Master Test Kit
  • Ammonia testing
  • Value priced
  • Excellent test lineup
  • Premium Choice
    Third place
    Tetra EasyStrips Aquarium Test Strips Tetra EasyStrips Aquarium Test Strips
  • Freshwater and saltwater use
  • Quick results
  • AQUA CARE PRO Aquarium Test Strips AQUA CARE PRO Aquarium Test Strips
  • Chlorine testing included
  • Affordable
  • Easy to use
  • capetsma 9 in 1 Aquarium Test Strips capetsma 9 in 1 Aquarium Test Strips
  • Freshwater, saltwater, pond, and pool testing
  • Testing for special situations
  • The 10 Best Aquarium Test Strips — Reviews 2021

    1. API 5 in 1 Freshwater & Saltwater Aquarium Test Strips — Best OverallAPI 5 in 1 Freshwater & Saltwater Aquarium

     

    The API 5 in 1 Freshwater & Saltwater Aquarium Test Strips include five tests for the necessary compounds to maintain a healthy environment. They take care of the major ones, such as pH, nitrite, and nitrate. They also measure general hardness and carbonate. The selection of tests and setups is interesting. For example, they provide more precise readings in the 6.0-9.0 range. Carbonate acts as a buffer against radical pH shifts.

    The product includes detailed and useful instructions. However, it also pitches many of the manufacturer’s products between steps. The test kit is geared toward established tanks, though we’d like to see dissolved oxygen as one of its components.

    Pros
    • Convenient
    • Narrow pH window
    • Affordably priced
    • Excellent instructions
    Cons
    • No test for dissolved oxygen

    2. API Freshwater Aquarium Master Test Kit — Best ValueAPI Freshwater Aquarium Master Test Kit

     

    The API Freshwater Aquarium Master Test Kit is one of the best aquarium test strips for the money. The price may seem high up front, but the strips cost only pennies a piece if you do the math. It has a different lineup of tests that include ammonia, nitrite, hardness, and pH for both freshwater and high ranges.

    The inclusion of ammonia is smart because it’s likely to cause the most problems early in the game. Monitoring nitrite levels while leaving out nitrates is another excellent move because the latter is always present in an established aquarium. This product is a great value if you have multiple tanks. Unfortunately, it’s only for freshwater use.

    Pros
    • Ammonia testing
    • Value priced
    • Excellent test lineup
    Cons
    • Freshwater tanks only
    • No dissolved oxygen test

    3. Tetra EasyStrips Aquarium Test Strips — Premium ChoiceTetra EasyStrips 6-in-1 Freshwater

     

    The Tetra EasyStrips Aquarium Test Strips include chlorine, which is helpful when you first establish your tank and when you do routine water changes. It’s curious that ammonia isn’t included, however.  The kit does test for hardness, alkalinity (a.k.a. carbonate), pH, nitrites, and nitrates.

    You can use the test strips in freshwater and saltwater tanks, which makes it a value purchase. This kit has a limited range for pH, between 6.2-8.4. We prefer this setup because including the enter scale doesn’t offer any value. This way, you can get more accurate results, which is always preferable.

    Pros
    • Freshwater and saltwater use
    • Quick results
    • Narrow pH range
    Cons
    • No ammonia testing

    4. AQUA CARE PRO Aquarium Test StripsFreshwater Aquarium Test Strips

     

    The AQUA CARE PRO Aquarium Test Strips include several useful measurements, including nitrites, nitrates, hardness, carbonate, chlorine, and pH. We think that it’s more helpful to know the ammonia level in a tank versus the nitrates, which only shows if the tank has had a long-running issue with its biological filtration.

    The manufacturer stands out on several scores. The instructions are clear and well-written. The customer support is also noteworthy. We liked that the product is a year’s supply, with extra strips thrown in when closer monitoring is needed. The color differences on the nitrites and nitrates are a bit too close in their hues, however. Otherwise, this value purchase is easy to use.

    Pros
    • Chlorine testing included
    • Affordable
    • Excellent customer support
    • Easy to use
    Cons
    • Nitrites and nitrates strips harder to read

    5. capetsma 9 in 1 Aquarium Test Stripscapetsma 9 in 1 Aquarium Test Strips

     

    The capetsma 9 in 1 Aquarium Test Strips include measurements for the necessary parameters of nitrites, nitrates, pH, carbonate, and chlorine. It also goes to the next level with copper and iron tests. The former is a smart idea if you have saltwater fish or koi, both of which are intolerant to high concentrations of copper. Testing for copper is also wise if your house has copper pipes or you’re on a well. Iron testing is essential if you have live plants in your tank.

    Depending on your setup, however, some of these tests won’t offer much extra value. The packaging says that it measures both carbonate and alkalinity, which are essentially the same thing. We can see it being helpful if you have fish with specific pH needs, but otherwise, it’s unnecessary.

    Pros
    • Freshwater, saltwater, pond, and pool testing
    • Testing for special situations
    Cons
    • Redundant tests with carbonate and alkalinity
    • Pricey

    6. Milliard Aquarium Test StripsMilliard Aquarium Test Strips

     

    The Milliard Aquarium Test Strips include both alkalinity and carbonate in this kit. Other parameters include nitrite, nitrate, pH, hardness, and chlorine. Without an ammonia test, this product seems more appropriate for an established tank instead of a new one.

    You can use the test strips on both freshwater and saltwater aquariums. They are easy to read, although there are issues with the colors bleeding and making testing difficult in some cases. However, the price is right for monitoring the essential elements of your tank’s water chemistry.

    Pros
    • Value priced
    • Freshwater and saltwater tanks
    Cons
    • Redundant tests with carbonate and alkalinity
    • Quality control issues

    7. BOSIKE Aquarium Test StripsBOSIKE Aquarium Test Strips

     

    The BOSIKE Aquarium Test Strips measure the necessary parameters of pH, hardness, nitrites, nitrates, chlorine (Cl2), and carbonate. They are appropriate for freshwater tanks only. Unfortunately, the hardness test won’t work, which is essential for saltwater species. On the positive side, the product is affordably priced, which makes testing convenient.

    The strips are easy to use and yield quick results. However, the hues are closely matched for some tests, which makes it hard to distinguish between the readings. The pH strip does have a narrow range for more accurate and meaningful results.

    Pros
    • Economically priced
    • Narrow pH range
    Cons
    • Not suitable for saltwater tanks
    • Ammonia testing not included

    8. SJ Wave 6 in 1 Aquarium Test StripsSJ WAVE

     

    The SJ Wave 6 in 1 Aquarium Test Strips take a different riff on the usual lineup, with both general hardness and carbonate. Curiously, there’s also a thermometer. Most aquarists probably already have one in their tank, making it an odd addition. It’s worth noting that this product is for freshwater tanks or ponds only.

    While we appreciate the manufacturer’s transparency with the shelf life, it’s essential to know up front that the product only lasts three months after you open the package. Unless you’re testing daily, which would be overkill on monitoring, you probably won’t use up all of these before they expire. The strips also bleed if you aren’t careful, which is another hit on its value.

    Pros
    • Ebook with instructions
    Cons
    • Short shelf life
    • Poor value

    9. EASYTEST 6 Way Aquarium Test StripsEASYTEST 6 Way Aquarium Test

     

    The EASYTEST 6 Way Aquarium Test Strips measure the usual suspects, along with chlorine and carbonate. They also cover hardness and chlorine, with no ammonia test included. The product is appropriately named, except when it comes to hardness. The differences in the shades are difficult to distinguish. This kit is just for freshwater setups and ponds.

    The manufacturer went the extra mile with its packaging, though. The bottle contains 50 strips, with the balance sealed to protect it while you go through the first lot. It’s unfortunate that this didn’t make them more accurate. The results are inconsistent at best and there are other quality control issues.

    Pros
    • Excellent packaging
    Cons
    • No ammonia test
    • Inaccurate results
    • Not suitable for saltwater

    10. Stript Health 7-Way Aquarium Test StripsStript Health 7-Way Aquarium Test Strips

     

    The Stript Health 7-Way Aquarium Test Strips promises much with the parameters that they claim to test. Unfortunately, they miss the mark on several scores. The strips are poorly made and will bleed if you aren’t careful when handling them. This makes them hard to read and puts into question their accuracy.

    On the positive side, the manufacturer offers a money-back guarantee. It also claims that the test strips have a 24-month shelf life. Our experience has been that they deteriorate quickly once you open the package. Unfortunately, there are other issues with the product that keep us from trying to find out for sure.

    Pros
    • Money-back guarantee
    Cons
    • Redundant tests for alkalinity
    • Inaccurate results
    • Bleeding test strips

    Buyer’s Guide

    The essential thing to remember about setting up an aquarium is that you’re creating a closed environment for your fish. In the wild, conditions stay relatively stable because of the large volumes of water. While a 20-gallon tank may seem like a large amount, it isn’t for your fish. Changes can happen quickly, often with disastrous results.

    The reason is that most fish aren’t adapted to handle this type of stress. Of course, it is a sliding scale of the degree to which some species will tolerate varying conditions. The best way to manage the water chemistry of your fish’s aquarium is through testing. Many things aren’t obvious by merely looking at your tank — unless your fish are gasping at the surface.

    Many pet stores will test your tank water for free or for a nominal charge. However, getting a kit makes it more convenient to monitor the conditions yourself. You can respond quickly to deteriorating water quality and reduce the amount of stress that your fish have to endure. Remember that stress can make them more vulnerable to disease and pest infestations.

    Things you should test include:
    • Ammonia
    • Nitrites
    • Nitrates
    • pH
    • Hardness
    • Dissolved oxygen
    • Chlorine

    Many of these factors are interconnected. If one thing is off, it can have cascading effects on the overall water quality. Regular testing can give you a complete picture of the health of your aquarium. It’ll also give you insight into the correct maintenance for your setup.

    Ammonia-Nitrites-Nitrates

    These three compounds are an example of the inter-related nature of water chemistry. Each one is part of the nitrogen cycle. Waste from your fish and plants first turns into ammonia, followed by nitrites and nitrates. The first is something you must monitor. High levels of ammonia can wipe out an entire tank of fish. The breakdown of this toxin occurs through biological filtration. These filters contain a medium that allows beneficial bacteria to develop. It can take up to 6 weeks before your tank has gone through the complete cycle, creating a stable environment for your fish.

    That’s one reason that you should introduce new fish slowly to your tank, to avoid overwhelming the system.

    Some kits will measure all three compounds. Ammonia and nitrite are the ones that you should track carefully, since both are toxic to fish and other aquatic organisms. Many products also include nitrates. Live plants will keep this last one in check because they’ll use it for nourishment. If you have artificial plants, though, nitrates can become problematic at high levels.

    pH

    PH measures the acidity of a tank. It can have a profound impact on your fish’s health and water quality for two primary reasons. First, it affects the solubility of the nutrients that they need to survive. That, in turn, determines whether the chemicals are in a form that your fish and plants can use.

    The pH of your tap water varies depending on where you live. For example, it tends to run more acidic in the eastern half of the United States than in the western half. It’s measured on a scale of 0-14, with 7 being neutral. The lower the pH, the more acidic your tank water is. The essential thing to understand is that it’s a logarithmic scale. A pH of 4 is 10 times more acidic than 3. Likewise, 5 is 100 times more.

    Fish vary in their preferences for pH, just like plants. You should stick to fish species with similar water chemistry needs so everyone can thrive. Heavy metals are more readily available at lower pH levels. Fish that are sensitive to these materials won’t survive long in an unhealthy environment.

    Hardness

    The water’s hardness has a direct impact on the pH too. If you have hard water, it has dissolved minerals, such as calcium and magnesium, in it. Those are what causes the deposits on your tank and its equipment. You may find it difficult to control your aquarium’s pH if that’s the case. The minerals will push the water toward the alkaline end of the spectrum.

    Many enthusiasts circumvent that problem by adding demineralized water to their tanks instead of tap water. It’s something that you should consider for the long-term health of your fish if it’s an issue in your area.

    You’ll see kits that measure both general hardness and carbonate. Both involve minerals. The former says more about your tap water than anything. The latter gauges how quickly your tank’s pH can fluctuate. These minerals can help keep it in the appropriate range to reduce stressing out your fish with drastic changes.

    Dissolved Oxygen

    Fish gasping at the surface of your tank can be an indication of poor water quality. But some species breathe air, so they will linger at the top occasionally. However, if you notice red or swollen gills, it’s probably the former condition. The problem is usually the concentration of dissolved oxygen.

    Several things can influence how much dissolved oxygen is available to your fish. Cooler water can contain more of this element than warmer temps. That’s why you must keep the temperature stable. It’s worth noting that there is no upper limit of oxygen concentration that crosses into harmful territory. The water gets saturated and that’s it.

    Brackish and saltwater tanks also have less dissolved oxygen available. Bear in mind that there is a finite amount of water with only so much space for so many molecules. The salt takes up the space that oxygen would use. The ideal concentration is 5-6 parts per million (ppm) for most fish. However, bigger fish need more, as do more active species.

    Chlorine

    If you’re using tap water for your tank, you must monitor the chlorine levels. Treated city water can contain chemicals that are harmful to fish, even at low concentrations. Chlorine will dissipate from the water if you keep the hood off for 24 hours. This is especially true with tanks that have a high ratio of length to depth. It’s another reason that you should wait before adding your first fish.

    You can get products that will remove chlorine from your aquarium’s water. You can also run an air pump in a bucket of water to get things moving along faster. The exception is if you’re on a well. While chlorine may pose no issues, you might have problems with iron or hard water that you’ll need to treat.

    Other Considerations

    One pet peeve with these products is poorly made strips that bleed or fall apart when they get wet. That’s often a problem with cheaper kits. Another factor is the ease of determining the results. We prefer test strips with different colors on the parameters’ scale instead of different shades of the same color, which often makes it hard to gauge your measurements accurately.

    Proper storage of test strips is imperative. It’s one thing to get a great deal on a hundred strips. However, that does little good if their shelf life is only a month. We recommend testing at least once a week for the major aquariums. You can do it more often if you make changes to your aquarium, such as getting a new filter or doing water changes.

    Those are the times when conditions are most likely to fluctuate and stress out your fish.

    Conclusion

    Monitoring your aquarium’s water chemistry is a vital part of tank maintenance. It ensures that unseen elements don’t affect your fish’s health adversely. The API 5 in 1 Freshwater & Saltwater Aquarium Test Strips are the best overall products for getting the job done.

    The API Freshwater Aquarium Master Test Kit makes it easy and convenient to maintain one or more tanks with one purchase. It’ll last a few years, depending on how often you test and how many tanks you have. Proper storage is essential to get your money’s worth.

    Monitoring the water chemistry of your aquarium is the best thing that you can do to ensure the health of your fish and plants. It can give you insights into how often you should do water changes and can help you stop problems in their tracks before they become more serious issues.


    Featured image credit: hineck, Pixabay