How To Use The API Master Test Kit Correctly!

The API Master Test Kit is a widely used tool in the fish-keeping hobby that accurately measures pH, ammonia, nitrite, and nitrate levels in aquarium water.

This kit is probably the most common option for aquarium enthusiasts to test and track their water parameters.

Although the API Master Test Kit is very beginner-friendly and easy to use, I’ve noticed many people on social media and forums asking questions about its usage before purchasing it. Therefore, I decided to publish this article to help my readers.

There are currently four variants of this test kit available:

  • API Freshwater Master Test Kit
  • API Saltwater Master Test Kit
  • API Reef Master Test Kit
  • API Pond Master Test Kit

In this article, I will be using the API Freshwater Master Test Kit, but the other kits work in a very similar way.

Pros

  • Easy To Use.
  • More Accurate Than Strips.
  • Tests A Wide pH Range.

Cons

  • Colors Can Be Difficult To Read.
  • Takes More Time Than Strips.
  • No Chlorine Test.

What Does The API Master Test Kit Test For?

API Master Test Kit Bottles
API Master Test Kit Bottles

The API Master Test Kit can test the pH, ammonia, nitrite, and nitrate levels in your aquarium, providing accurate readings within minutes.

Since most of the fish I keep are softwater species, I don’t have much use for the high-range pH test formula included in the kit.

My main criticism of the API Master Test Kit is that I would prefer a chlorine test to be included instead of the high-range pH test.

Many hobbyists may not need the high-range pH test, but almost everyone will need to check chlorine levels after a water change.

How To Use The API Master Test Kit!

API Master Test Kit
API Master Test Kit

Here’s the easiest way to use the API Master Test Kit:

  1. Add around 5 ml of aquarium water to the included test tubes.
  2. Add the required number of test solution drops to the test tube.
  3. Shake the test tube a few times to mix the aquarium water and test solution drops.
  4. Wait 2-3 minutes for the water to change color.
  5. Compare the color of the water with the included chart to get your reading.

It’s really that simple, and the included user manual provides a detailed breakdown of the process.

You can usually take a full set of readings with the test kit in about five minutes.

While the API Master Test Kit takes a bit longer than aquarium test strips, it is far more accurate and easier to read in my experience.

Adding Water To The Test Tubes

I usually dip the test tubes into my aquarium to collect around 5ml of water. Sometimes I need to pour out a small amount, but I prioritize speed over precision since getting exactly 5ml can be surprisingly time-consuming.

Some people use 5ml pipettes for this step, as it provides a quick, easy, and inexpensive way to measure out 5ml of water from the aquarium.

Water Levels In Test Tubes
Water Levels In Test Tubes

As you can see in my photograph above, I focus on getting as close to 5 ml of water in the test tube as possible but I usually have a little more than that and the tests work fine.

How Many Drops To Use
How Many Drops To Use

Here’s a quick tip: the number of test solution drops required for each test is listed both in the booklet and on the front of the test solution bottle.

I took a while to figure this out when I first started using the API Master Test Kit, so this can save you a bit of time with each test.

How to Test pH with the API Master Test Kit

The API Master Test Kit includes both a standard pH test and a high-range pH test. The high-range test is more specialized for hard water aquariums.

As I mentioned earlier, most freshwater fish keepers will be fine with the regular pH test. I’ve never actually used the high-range test because all of my tanks have soft or neutral water.

Testing Regular pH Ranges

API Master Test Kit ph Test
API Master Test Kit ph Test

Here’s how to test regular pH ranges with the API Master Test Kit:

  1. Add 5 ml of aquarium water to one of the included test tubes.
  2. Shake the pH test solution bottle and add 3 drops of the solution to the test tube.
  3. Cap the test tube and gently invert it a few times or shake it for 2-3 seconds.
  4. Wait 30-60 seconds for the water to change color.
  5. Compare the color of the water with the pH color chart to determine your reading.
Testing pH Levels

I’ve noticed that the regular pH test can sometimes give an artificially high reading, with the water turning a deep shade of blue.

This issue might be caused by some of the test solution getting trapped in the dropper and oxidizing, which can affect the accuracy of the next test.

If this happens, release a few drops of the test solution onto a tissue to remove the oxidized solution from the dropper, then shake the bottle before running the test again.

Testing Higher pH Ranges

API Master Test Kit High Range ph Test
API Master Test Kit High Range ph Test

This is how you test higher pH ranges with the API Master Test Kit:

  • Add 5 ml of water to a clean test tube.
  • Shake the high-range pH test solution bottle and add 5 drops to the test tube.
  • Cap the test tube and shake it for 2-3 seconds.
  • Wait around one minute for the water to change color.
  • Compare the color with the color chart to take your reading.
Testing High Range pH Levels

If you have a soft water or neutral aquarium, there’s usually no need to use the high-range pH test, as the regular pH test solution will provide an accurate reading.

However, if you have a hard water aquarium, this high-range test can be very useful. In that case, you can skip the regular pH test and use the high-range test instead.

How To Test Ammonia With The API Master Test Kit!

API Master Test Kit Ammonia Test
API Master Test Kit Ammonia Test

This is how you test the ammonia levels in your aquarium with the API Master Test Kit:

  • Add 5 ml of water a test tube.
  • Shake both ammonia test solution bottles and add 8 drops of the solution from bottle #1 to the test tube.
  • Wait around five seconds and add 8 drops of the solution from bottle #2 to the test tube.
  • Cap the test tube and shake it for a couple of seconds.
  • Wait 5 minutes for the color to develop in the water.
  • Compare the watercolor with the ammonia color chart.
Testing Ammonia

I highly recommend implementing the 5-minute waiting period with this test, as the solution can pass through several color stages as it develops.

If you only wait a minute or two, you might mistakenly think your ammonia levels are lower than they actually are because the test solution hasn’t fully developed its color.

Additionally, note that the test solution from bottle #2 tends to come out of the dropper faster than the solution from bottle #1.

Keep this in mind and apply gentle pressure when releasing the test solutions.

How To Test Nitrite With The API Master Test Kit!

API Master Test Kit Nitrate Test
API Master Test Kit Nitrite Test

This is how you test nitrite levels with the API Master Test Kit:

  • Add 5 ml of water to a test tube.
  • Shake the nitrite test solution bottle and add 5 drops of the solution to the test tube.
  • Cap the test tube and invert the test tube a couple of times.
  • Wait around five minutes for the color to develop.
  • Compare the watercolor with the nitrite color chart to take your reading.
Testing Nitrite Levels

Although API recommends waiting about five minutes for the color to develop in the nitrite test solution, I have found that the color stabilizes after about two minutes.

It is rare to see the shade of blue change after a couple of minutes, but tanks with higher nitrite levels may require the additional time.

Therefore, I still recommend waiting the full five minutes if you suspect higher nitrite levels in your tank to ensure you get an accurate reading.

How To Test Nitrate With The API Master Test Kit!

API Master Test Kit Nitrate Nitrate Test
API Master Test Kit Nitrate Nitrate Test

Here’s how to test nitrate levels with the API Master Test Kit:

  1. Add around 5 ml of aquarium water to one of the test tubes.
  2. Shake the first nitrate test solution bottle for a couple of seconds and add 10 drops of the solution to the test tube.
  3. Vigorously shake the second nitrate test solution bottle for at least 30 seconds and then add 10 drops of it to the test tube.
  4. Cap the test tube and shake it vigorously for 60 seconds.
  5. Wait 5 minutes for the color to develop.
  6. Compare the water color with the nitrate color chart to determine your reading.
    Testing Nitrate Levels

    The test solution in bottle #2 requires vigorous shaking to provide an accurate test and needs a longer shaking period compared to the other tests in the API Master Test Kit.

    Unlike the other tests, the nitrate test also requires you to vigorously shake the capped test tube with both solutions added to ensure accuracy.

    I tested this by taking water from one of my tanks and splitting it into two separate test tubes. After performing the test, one vigorously shaken and the other not, both resulted in different colors, demonstrating the importance of thorough shaking.

    How Accurate Is The API Master Test Kit?

    A Complete API Master Test Kit Test
    A Complete API Master Test Kit Test

    The API Master Test Kit is impressively accurate, especially considering its price and the testing method used.

    While more precise testing options are available, they are significantly more expensive and not necessary for most aquarium hobbyists.

    One potential issue with the API Master Test Kit is that the color comparisons can be a bit challenging to read. The solid color rectangles on the chart might not be the most effective way to present the information.

    In my opinion, a single line with a color gradient and the corresponding ppm readings alongside the different colors would be a better option. However, the majority of users should still find the current system adequate.

    API Master Test Kit And Test Strips
    API Master Test Kit And Test Strips

    I have used several different water test strips for my aquariums, and they were all difficult to read and often gave inconsistent results.

    This inconsistency is expected due to their low price, speed, and ease of use. However, I prefer using something like the API Master Test Kit to get a more accurate reading, especially if I suspect there might be an issue with my tank’s water parameters.

    Ammonia Test Strips
    Ammonia Test Strips

    My photograph above shows the API ammonia test strip reading, and as you can see, it is extremely difficult to interpret since it displays two valid colors on the strip.

    While you could average these colors and estimate a 0.75 ppm ammonia reading, I never trusted these particular strips due to consistent issues like this.

    All In One Test Strips
    All In One Test Strips

    My photograph above shows the results of the Easytest 7-Way Test Strips, which, as you can see, do not measure ammonia levels.

    I still use these test strips in my tanks, but almost exclusively for checking chlorine levels after a water change. For other readings, I rely on the results from my API Master Test Kit.

    How Many Tests Can The API Master Test Kit Do?

    800 Tests Per Kit
    800 Tests Per Kit

    The API Master Test Kit is technically capable of performing 800 tests per kit, but in practice, the actual number is significantly lower.

    As mentioned earlier, most users won’t need both pH tests in the kit, as either the regular pH test or the high-range pH test will suffice for their tank, leaving one bottle of test solution unused.

    Typically, users will want to check ammonia, nitrite, and nitrate levels simultaneously, which I consider a single test session.

    A notable issue is that the nitrate test requires 10 drops of solution, the nitrite test requires 5 drops, and the ammonia test requires 8 drops. Consequently, you will run out of nitrate test solution and nearly exhaust the ammonia test solution while still having half a bottle of nitrite test solution remaining.

    Although there are inexpensive refills available, the average fish keeper will get significantly fewer than 800 tests from this kit.

    Final Thoughts

    The API Master Test Kit stands as a popular and efficient choice for monitoring aquarium water parameters.

    While offering detailed insights into pH, ammonia, nitrite, and nitrate levels, its user-friendly nature ensures ease and accuracy over test strips.

    However, the kit could be enhanced with the inclusion of a chlorine test and a clearer color comparison chart.

    Whether for beginners or experienced hobbyists, the API Master Test Kit proves indispensable in maintaining a healthy aquatic environment.