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Salifert Test – Nitrate


Salifert Test – Nitrate is for testing the nitrate level of your aquarium water. This test is ideal for saltwater aquariums.

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Salifert Test – Nitrate (NO3) is for testing the nitrate level of your aquarium water.

This Salifert Profi Test kit is suitable for marine use.

This kit will measure between 0 – 100ppm of nitrate.

If the nitrate value is lower than 10ppm you can use the low range colour comparison to increase the accuracy. This means looking from the side of the test vile (rather than through the top). When looking through the side the colour is amplified approximately 10 fold. Simply divide the colour chart value by 10 to see how low the nitrate is. For example 2 will become 0.2.

Nitrate is an end product of fish waste. When fish make waste, they produce ammonia. Aquarium bacteria gets to work and changes ammonia to nitrite. Then nitrite to nitrate. Nitrates are best kept under control by performing regular partial water changes.

What should my nitrate level be?

In most aquariums we aim for nitrates to be as low as possible. It does depend on what type of animals you have as to how much nitrate they will tolerate. Some animals and plants need a little nitrate to be in the water to thrive. You can use carbon dosing products like NO3:PO4-X to control nitrate and phosphate. Nothing beats also keeping up with regular aquarium maintenance though!

As a rough guide, aim to keep your nitrate level below 25ppm. The lower the better in most set ups. Some corals will not tolerate such high levels and prefer the nitrate to be under 5ppm or even lower.

How can I control algae in a reef tank?

If you have a lot of unwanted algae growth, it is worth checking your nitrate levels. If they are high, this could be the cause of your algae problems. It is worth doing a few partial water changes and sucking out as much waste as possible with a siphon cleaner to reduce nitrates.

If after this you are still getting algae problems, check how long you have your lights on for. Too much light can cause algae to grow more quickly. Use a timer to ensure that you don’t accidently leave your aquarium lights on for too long.

Another potential cause of unwanted algae is high phosphate levels. Phosphate (PO4) is another waste level. It is not as harmful to most animals as nitrate.

Your nitrates and phosphates should be in an ideal balance of between 50:1 – 12:1 depending on what corals you wish to keep. You can find out more about which levels are right for you by looking at Red Sea Reef Care Recipes.

Here at Cornwall Aquatics we aim for a nitrate – phosphate balance of 16:1. For example, if your nitrate level is 1ppm, we would try to keep your phosphate at around 0.06ppm.

In most reef aquariums try not to let phosphate go above 0.1ppm. If your phosphate is much higher than it should be, try using a resin exchange media like RowaPhos to reduce the levels.


There are other ways to tackle algae problems but the above is a great starting point. If you need further help, one of our aquarists can book in with you for an aquarium health check.

Top Tip:

It is important not to overfeed your tank as this can lead to higher waste levels. Feed as much as your fish can eat fairy quickly. In normal circumstances, frozen or dry foods should all be eaten within 30 – 60 seconds. Live foods aren’t so much of a problem because they can live in the tank for a while so it is fine to feed a bit more.


The Salifert Nitrate Profi Test contains enough reagent to test 60 times.


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