The Salty Side: Saltwater Aquariums for Beginners

Maintaining consistent and correct levels in your tank is the key to a successful aquarium, and there is no other way to establish what your tank is doing without testing the water with saltwater aquarium test kits.

From the moment you begin to cycle your tank you need to get into the habit of habitually testing your water on a regular basis. Without regular testing, the water in your glass box will be left to it’s own devices resulting in potential algae and cyanobacteria problems. The thought of introducing corals to untested water would be wholly ill advised.

Where do we begin?  I’ll break it down into two parts, the first part for what to test for during the cycling process and secondly, what to test for after your system has cycled and as a part of routine maintenance. 

What to test my saltwater tank for during cycling

When you first set up your tank and the system is experiencing its very first nitrogen cycle, there are three tests that are required to determine at which point the cycle is in.


When starting a new saltwater tank, the beginning of the cycle is kicked off by the presence of ammonia in the system. Ammonia will always be present in a saltwater tank in very low concentrations (which you will not pick up on a test kit) as it is an essential part of the nitrogen cycle. However, when first starting a tank it can be highly toxic to aquatic life because it can be found in excessive amounts.


Nitrite is the result of ammonia being converted by bacteria. When you test positive for nitrite, that means that the cycle is moving along.  Nitrite, the second indicator of the nitrogen cycle is toxic to aquatic life in excessive amounts.


Once you have tested positive for nitrate you know that the nitrogen cycle has been established, but before you can add any fish or invertebrates you need to wait for both the ammonia and nitrite to be unreadable on your test kits.

As well as setting up a new saltwater aquarium, ammonia test kits are imperative when running a quarantine tank for new fish and invertebrates.  High ammonia levels are a common reason fish die in quarantine.  

Nitrite test kits are very rarely used beyond establishing the nitrogen cycle.  It will be your choice to decide if they are a purchase you would like to make or instead rely on your local fish store (LFS) to test your water samples.  When I first set my system up, I decided that I did not want to be reliant on anyone else to test my water as I wanted full control.

The test kit for nitrate is an important one.  Not only will you use it to determine that the nitrogen cycle is in place but it will be required on a continuous basis from then on.

What to test my saltwater tank for after cycling

As mentioned above, you will always need a nitrate test kit, both during and after tank cycling.  Another purchase which is just as important as nitrate is the phosphate test kit. Both nitrate and phosphate levels will need to be checked on a regular basis to ensure you have control of both nutrients.

The idea phosphate range should be between 0.03ppm to 0.12ppm, depending on your coral requirement.

The ideal nitrate range should be between 0.2ppm and 5ppm although it can be higher.

Should you decide you want to move onto keeping coral, the three most important elements to keep a watchful eye on are kH/alkalinity, calcium and magnesium.

If you are interested in keeping tabs on your PH then a Salifert kit will do the job.  But it’s important to note that PH is affected by so many variables.  It is one of the test kits that more seasoned reefers will tell you its not worth having and chasing results.

What is the best test kit for a saltwater aquarium

Unfortunately there does not exist a single box of tests which encompasses every test you need to take.  Therefore, it is important to know what you need to test, in order to determine the test kit you need to buy.

Of the many brands available, Salifert is considered the most cost effective and accurate for the money. Many reefers chose to stay with Salifert, while others use Salifert for some of their tests and different brands for other.

Testing trace elements in a saltwater aquarium

The most common brands are very insistent on selling you test kits for things like Iodine, Strontium, Potassium, Copper … the list is endless. 

In my experience, keeping a fully stocked SPS and LPS tank, I have not felt it as necessary to test for these individual trace elements.  I have constantly dosed trace elements which ensures they are always available in my system.

The list of test kits I use to maintain my tank are as follows:

Nitrate – Salifert Test Kit, Red Sea Nitrate Test Kit and for values under 4ppm Red Sea Nitrate Pro Test Kit
Phosphate – Salifert Test Kit and Red Sea Phosphate Pro Test Kit.
KH, Ca and Mg – Salifert for all three.

Are API test kits accurate?

It is worth saying that a lot of beginners are sold the API test kit, which does encompass just about every test.  But, they soon realise that API does not stand up to scrutiny and falls short as far as accuracy of results is concerned.  I have not used API myself, but have heard and read an awful lot of negativity resulting from a purchase so in my opinion, they are probably best to steer clear of.

So there you have it!

In summary, the most important test kits to have when owning a saltwater aquarium are:

Ammonia – This is needed in the very beginning, but will probably never use again unless you decide on running quarantine tank.
Nitrite – Also needed in the very beginning, but will probably never use again.
Nitrate – Used to check that the nitrogen cycle is established, and then weekly to monitor levels.
Phosphate – Used weekly to monitor levels.

If you decide to keep corals:

KH – Used to check alkalinity levels weekly.
Ca (Calcium) – Used to check calcium levels weekly.
Mg (Magnesium) – Used to check magnesium levels weekly.

There are so many different choices of test kits out there and each brand has its own dedicated uses. My preferences are Salifert and Red Sea, both of which I have found to be very reliable.

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