Essential Aquarium Water Test Kits 1

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The quality of water in an aquarium is very much like the quality of air we breathe. Like us, all marine life requires that their environment fall within a certain range in order to maintain health and life. When it falls out of that range in one way or another it affects health and eventually, it could lead to death.

Those of us who deal with air pollution on a daily basis can likely empathize with our gilled friends: it isn’t fun if your environment is yucky. It seriously affects quality of life and can lead to health problems that aren’t easy to fix and sometimes, can’t be fixed at all.

That’s why it’s important to always to keep a close eye on your aquarium water parameters.

In this post, we’ll take a quick look at the important water parameters for both freshwater and saltwater aquariums and the essential water test kits that you should have.

Essential Aquarium Water Test Kits

Because of the delicate ecosystem in an aquarium, it’s important to invest in aquarium water test kits if you are serious about keeping fish happy and healthy. A lot of tests work for both saltwater and freshwater aquariums simply because the two tanks are not as different as one might think.

While this isn’t always the case, much of the time the same things that are unhealthy for saltwater fish are also dangerous to freshwater fish and vice versa. Though in some cases, some tests simply are not applicable, particularly when it comes to freshwater tanks and saltwater concerns.

Saltwater Parameters


Perhaps the most obvious parameter for a saltwater aquarium is the salinity: salt content. The salinity is how dense dissolved ions are in your water. This is measured with a hydrometer and is called specific gravity. 1.02 is the best S.G. measurement for most saltwater tanks.

Ammonia, Nitrates and Nitrites

While they are natural bi-products of the nitrogen cycle within your tank, these three chemicals are toxic. Once established, good bacteria growing in your tank breaks down nitrates, ammonia and nitrites so that it is safe for your fish. When you first set up your tank, this colony of bacteria doesn’t exist yet, so the levels are high. If something is wrong with your bacteria colony, then these toxic chemicals will be present in your water and you’ll need an aquarium water test kit to find them.


Calcium is actually very important in saltwater tanks, particularly tanks that have corals in them or other living things that need a lot of calcium to thrive. While this depends a lot on what’s living in your tank, the acceptable amount of calcium is usually somewhere within the range of 350 to 450 ppm (parts per million).


Magnesium has been in our oceans ever since Earth has had them, though it is often pretty low. It is essential in all living things, including the development and growth of marine life. The oceans usually have about 1280 ppm (it is way lighter than calcium, therefore higher) and your saltwater

Saltwater Aquarium Water Test Kits

Nitrite, Nitrate and Ammonia

Often times test kits are sold individually, but they can also be bought together to potentially save money. One of these kits will test for levels of the three toxic offenders listed above.

API has a Saltwater Master Test Kit that tests for these three chemicals in addition to checking your pH levels. It has consistently gotten good reviews for both ordinary saltwater tanks and reef tanks.

API Saltwater Master Test Kit

API Saltwater Master Test Kit


Companies like API and Red Sea both provide test kits that will check only the calcium levels in your water to ensure that your tank has levels that determine if your tank is thriving or not. API is affordable and a reliable company to purchase your test kit from.


Because magnesium is important to the pH levels and calcium consumption in your tank, it’s important to keep an eye on that. Some comprehensive kits come with this, but you can also purchase it individually. Salifert has a test kit that provides up to 50 tests and has received good reviews on ease of use and reliability.

Salifert Magnesium Test Kit

Salifert Magnesium Test Kit

Reef Tests

A specialized kind of saltwater aquarium, reef tanks are popular with more experienced hobbyists because of the special care they require. Calcium levels in particular need to be monitored more carefully, but they are also generally delicate tanks. You can use ordinary tests on them however, many companies offer a multi-test pack that aides in upkeep and maintenance for them specifically. The Red Reef Foundation kit by Red Sea offers calcium, pH level and magnesium tests for reef tanks. The kit includes 60 or more tests per element, making it a reasonably priced and smart purchase.

pH Kits

pH aquarium water quality test kits make sure that your water remains stable. While not as important as some other tests, erratic levels can still subject your fish unneeded stress and eventually, might make them ill. Like many other tests, API has something for this too in the form of test strips for both saltwater and freshwater tanks.


While not commonly found in saltwater, copper is actually used to help medicate saltwater fish. In high enough doses though, it is actually toxic to them. So, it is important to get a copper testing kit when it inevitably becomes time to see to the health of an ill fish. Copper test kits are pretty common in pet stores and are marketed to saltwater tanks. An alternative that might be less expensive is API’s Copper Test Kit.

Freshwater Parameters

Ammonia, Nitrites and Nitrates

Like with saltwater tanks, ammonia, nitrate and nitrite levels are very important in freshwater ones. Once your tank has finished cycling (those first few weeks that it’s been sitting there empty), a colony of good bacteria has grown in the filter and has eaten up these toxic chemicals. If all is well, your aquarium water test kit shouldn’t find any at all. If it does, it means something is wrong in your tank’s nitrogen cycle.

pH Levels

Most fish aren’t too picky when it comes to pH levels, at least outside of breeding time. But nonetheless, it is good to know the natural pH level is 7. If this number is below 7, the water has a higher acidity. Anything higher than a 7 has higher alkalinity levels. Most fish are fine as long as the number remains steady and isn’t too extreme in one direction or another. Also, do not use distilled water as this will cause a high pH balance and be potentially dangerous for your fish.


You wouldn’t think so, but salt is actually important to your freshwater tanks too. Salt isn’t generally present in freshwater but, if you are treating sick fish, you may be adding salt to your water for illnesses and to reduce stress. While most freshwater aquarium salt water test kits do not test for this, if you are unsure about the amount of salt in your aquarium, you should do a water change of at least 20% of the water to help reduce it.

Freshwater Aquarium Water Test Kits

Nitrite, Nitrate and Ammonia

Just like with saltwater aquariums, these are important chemicals to watch out for. If they are there, it is bad for your fish and all three can be tested for individually or together, depending on your purchase. API’s Saltwater Master Test Kit tests for the exact same things, but you can also buy their 5-in-1 kit and an ammonia kit relatively inexpensively. This gives you the added benefit of testing your pH levels too.

pH Kits

Aquarium water quality kits that test pH levels make sure that your water remains stable so that your fish aren’t subjected to unneeded stress. API’s test strips work with both freshwater and saltwater, and they are very inexpensive compared to some other brands.

API pH Test Kit

API pH Test Kit

Most people come into fish keeping with the preconceived notion that saltwater tanks are too much of a headache and not worth the effort, expense or time consuming. The truth is that they aren’t that different!

Both tanks require care and attention; the biggest difference between them is that saltwater tanks require a few more supplies and one or two additional aquarium water quality test kits to maintain.

All in all diligent care, consideration and frequent water changes will keep your aquarium water quality excellent so that your fish flourish. The reward for all that hard work is watching a tiny, colorful world thrive right in front of you every day.

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About Dennis Hanson

Dennis is an experienced aquarist with many years of knowledge and experience in keeping successful tanks. He also has no relations to the pop group Hanson.

One comment on “Essential Aquarium Water Test Kits

  1. Reply Smo Jul 29,2017 4:49 am

    Thx..great info..I’m sold..Great deal on Amazon

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