Everything you need to know about aquarium water testing with Checkers

Hanna’s range of aquarium Checkers is the ideal solution for measuring key parameters in your tropical or freshwater fish tank. Our comprehensive range of digital testers offers an accurate, reliable way to measure water quality in aquariums with no guesswork, providing the information needed to keep your fish and plant life healthy.

We cover everything you need to know about Checkers in this comprehensive guide. Ready to buy? Shop the full range of Hanna Checkers online here today, with free next-day delivery for all products in stock.

What are aquarium Checkers?

Aquarium Checkers are palm-sized, digital water testers for aquariums that measure a single parameter. These practical meters provide an accurate, electronic way to measure vital levels of specific parameters in fish tanks, including ammonia, phosphate, nitrate and magnesium. Checkers are designed to be easy to use for daily and weekly testing, with a simple single-button operation and easy step-by-step instructions for measurement. 

Checkers use reagents that react with your water samples. This reaction is measured by the electronic tester, providing clear results on a large LCD screen. Each Checker includes a starter kit of reagents in the box, allowing you to start testing immediately, with reagent refills available online directly from Hanna to stock up on tests. Browse the full range of Hanna aquarium digital testers here.

What’s the difference between test strips vs digital testers?

Using testing strips is one of the most common options for measuring the water quality of aquariums. However, testing strips rely on your own personal perception of the results. Typically, test strips include a colour wheel or chart to compare the colour of the test strip. If your determination of the results is inaccurate, or the range for a specific colour is wide, this may lead to over or underdosing your water when managing the levels of parameters in your aquarium.

Digital testers for fish tanks like Hanna Checkers remove the need to identify results yourself. The measurement of your tested parameter is displayed clearly on an LCD screen once the testing process is complete, providing exceptional precision when determining how best to manage or dose your aquarium water. Checkers take the guesswork out of testing for your peace of mind.

How do you measure aquarium water with Checkers?

Checkers allow you to measure the water in a fish tank in four simple steps:

  1. ‘Zero’ the Checker with your vial & 10 ml water sample inside

  2. Take your vial out and add your reagent

  3. Place your vial into your Checker

  4. Press the button and read the results

The directions for the specific parameter you are measuring are included as a step-by-step tutorial in the manual of the Checker, included in the box. Alternatively, you can find a digital version of specific Checker manuals on each product page, allowing you to easily and quickly follow the steps needed to measure the water quality in your aquarium. We cover steps for a range of different specific Hanna Checkers below.

For more information about how to test the water in your aquarium with Hanna Checkers, see our article here.

Which parameters should you measure in fish tanks?

The type of parameters you need to measure depends on a few factors, including the types of plants, fish and corals you keep. The type of aquarium you have also influences which parameters you should measure:

Freshwater tanks

• pH: the pH level of an aquarium determines its alkalinity or acidity. Most freshwater aquariums should be between 6.0 and 7.0 pH.
• Ammonia: this parameter is a product of waste in your aquarium and should be as low as possible to prevent harm to plants and fish.
• Nitrite: this parameter is a part of the nitrogen cycle and is toxic to fish.
• Nitrate: this parameter is also produced from the nitrogen cycle and can cause algae to bloom, reducing the available oxygen for fish.
• Carbonate hardness: this parameter indicates whether the water can buffer acidity effectively, which is required to maintain balance within the tank.

See our article here for more information about the best parameters to measure in freshwater tanks.

Marine tanks

• pH: the pH level of an aquarium determines its alkalinity or acidity. Most saltwater aquariums should be between 81.-8.4 pH.
• Ammonia: this parameter is a product of waste in your aquarium and should be as low as possible to prevent harm to plants and fish.
• Nitrite: this parameter is a highly toxic product of the nitrogen cycle, requiring monitoring and management within marine tanks.
• Nitrate: this parameter is part of the nitrogen cycle and can indirectly lead to an algal bloom, reducing oxygen.
• Phosphate: this parameter is vital to coral growth, though too high levels can lead to algae growth.
• Alkalinity: this parameter acts as a buffer, preventing fluctuations in pH that could harm fish, corals and plants.
• Magnesium: this parameter is consumed by coral, and an optimal level is required for its successful growth and development.
• Calcium: coral skeletons are made from calcium carbonate, requiring a consistent level of this parameter for healthy growth.

See our article here for more information about the best parameters to measure in reef tanks.

Measuring specific parameters with digital Checkers

Freshwater ammonia

Our bestselling HI-715 Medium Range Ammonia Checker provides peace of mind when monitoring ammonia levels within freshwater tanks. The steps for testing are as follows:

1. Press the button to turn the meter on, fill your vial with a sample of aquarium water and place it in the Checker
2. Press the button to ‘Zero’ the Checker, then remove the vial
3. Add 4x drops of reagent A to the vial, swirl to mix and repeat with reagent B, then re-insert the vial for measurement
4. Press and hold the button to start the timer and wait for your results in mg/L (ppm) of ammonia nitrogen

Learn more about ammonia in freshwater aquariums here.

Marine ammonia

The HI-784 Marine Ammonia Checker is a popular choice of aquarium tester for measuring this key parameter in saltwater tanks. The steps for testing are as follows:

1. Add 1ml of reagent A into the clean, dry vial and add one packet of reagent B before using a pipette to fill the vial up with your water sample to the 10mL mark
2. Gently shake your sample to dissolve the reagent and allow it to stand for 30 seconds before placing it in the Checker and pressing the button
3. Remove the vial, add one packet of reagent C and shake gently for 30 seconds to dissolve before re-inserting the vial into the Checker
4. Press and hold the button to start the timer and wait for your results in ammonia/ammonium ppm NH3

Learn more about ammonia in marine aquariums here.

Phosphate

The HI-713 Low Range Phosphate Checker provides an accurate way to test phosphate in both saltwater and freshwater aquariums. The steps for testing are as follows:

1. Press the button on the Checker, then fill your vial with a sample of water from your fish tank water and place it in the tester
2. Press the button to ‘Zero’ the Checker before removing the vial
3. Add the contents of one packet of reagent to the vial and shake gently for two minutes, ensuring the powder is dissolved before you place it back in the Checker
4. Press and hold the button to start the timer and wait for your results in ppm

Learn more about phosphate in both marine and freshwater aquariums here.

Marine nitrate

The HI-782 High Range Nitrate Checker is one of the best options for measuring nitrate within saltwater and reed aquariums. The steps for testing are as follows:

1. Press the button on the Checker, then fill the vial with a sample of aquarium water and place it in the tester
2. Press the button to ‘Zero’ the Checker before removing the vial
3. Add the contents of a single packet of reagent into the vial and shake vigorously for two minutes before you place it back in the Checker
4. Press and hold the button to start the timer and wait for your results in ppm

Learn more about nitrate in saltwater aquariums here.

Marine magnesium

Hanna’s HI-783 Marine Magnesium Checker is an accurate and reliable solution for testing magnesium within coral and marine fish tanks. The steps for testing are as follows:

1. Press the button on the Checker, fill the vial with 4mL of reagent A and then add 5mL of water sample, inverting the vial to mix before inserting it into the Checker
2. Press the button to ‘Zero’ the Checker before removing the vial
3. Add the contents of a single packet of IND reagent into the vial and gently shake for 30 seconds to dissolve before you place it back in the Checker
4. Press and hold the button to start the timer and wait for your results in ppm

Learn more about magnesium in marine aquariums here.

Nitrite

The HI-707 Low Range Nitrite Checker is a suitable option for the measurement of both marine and freshwater aquariums to identify the level of nitrite in the water. The steps for testing are as follows:

1. Press the button on the Checker, then fill the vial with a sample of aquarium water and place it in the tester
2. Press the button to ‘Zero’ the Checker before removing the vial
3. Add the contents of a single packet of reagent into the vial and shake gently for 15 seconds to dissolve before placing the vial back in the Checker
4. Press and hold the button to start the timer and wait for your results in ppb of NO2−N

Learn more about nitrite in both freshwater and saltwater aquariums here.

Alkalinity dKH

The HI-772 Marine Alkalinity Checker is the ideal tester to measure Alkalinity dkH in saltwater aquariums. The steps for testing are as follows:

1. Press the button to turn the meter on, fill your vial with a sample of aquarium water and place it in the Checker
2. Press the button to ‘Zero’ the Checker, then remove the vial
3. Add 1 mL of S reagent to the sample, replace the cap and gently invert five times to mix
4. Press and hold the button to start the timer and wait for your results in dKH

Learn more about alkalinity in marine aquariums here.

What is the best practice for measuring aquarium water?

Following best practices when measuring the water in your aquarium is key to achieving accurate and reliable results. Forming habits for consistent measurement and measuring the correct parameters are vital to the health of your aquarium and the fish, coral or plant life within. Here are a few pointers to consider for best practice:

• Regularity: testing often is key to spotting swings in water chemistry as quickly as possible, allowing you to make adjustments before problems occur
• Consistency: testing at the same time every day or week can help you form a routine and prevent changes in parameters from being missed
• Parameters: the type of water in your aquarium and the fish you keep will influence which parameters are the most important to monitor
• Method: using a digital tester provides peace of mind and ensures your aquarium water is accurately measured

Learn more about best practice for aquarium testing here.

Where to buy digital testers for aquariums

Hanna stocks a complete range of digital testers for fish tanks online. Our accurate electronic Checkers are a reliable solution for consistently measuring aquarium water, with none of the guesswork of test strips. Browse the full range of Hanna Checkers online here, with free next-day delivery on all Checker orders.

Need reagents for your Hanna Checker? All the reagents you need for testing aquarium water are also available directly through our website. Each Checker includes a starter kit of reagents, with the specific reagent number included on the packaging for easy reordering.

For advice on the best Hanna digital Checkers for your aquarium, get in touch with our experts directly. Call 01525 850 855 or email us at sales@hannainstruments.co.uk today.