Back to Testing

Salifert Test – Calcium


Salifert Test – Calcium is for testing the calcium level of saltwater aquariums. It is important that the calcium level is right because it helps fish and invertebrates (especially corals) to grow in a healthy way.

6 in stock


Salifert Test – Calcium is for testing the calcium level of your aquarium water.

This Salifert Profi Test kit is for testing saltwater (not freshwater).

It is important that the calcium level is right for your animals. Calcium helps fish and invertebrates (especially corals) to grow in a healthy way.

What is a good calcium level for coral growth and coral colour?

Natural seawater has a calcium level of around 415ppm. In an aquarium, you should always aim to keep your calcium level above 400ppm.

Red Sea Recipes recommend parameters between 410ppm – 465ppm depending on which type of reef aquarium you have. You will tend to find that coral colouration will be better when the calcium level is kept to the lower end (around 410 – 430ppm). However, coral growth will be better if you keep the calcium to the higher end (430 – 465ppm).

Foundation elements

The foundation elements are the essential building blocks of coral skeleton. If they are not available in the correct ratios, one of them will quickly become a limiting factor. Over 90% of coral skeleton is comprised of calcium carbonate, which is made by combining calcium and carbonate ions from the water. This combination can form a strong crystal structure known as aragonite or a more brittle crystal structure known as calcite. In unbalanced conditions (eg. where there are relatively low levels of magnesium) the skeleton will develop with a higher proportion of calcite. This would make a coral more brittle and more susceptible to damage.

Regular testing

It is important to keep the right balance between the foundation elements; KH, calcium and magnesium. This is especially important to achieve healthy coral growth. We recommend checking these three parameters at least once a week and buffering with a calcium additive if necessary. It is easy to test once you get the hang of it. If you need any help or advice our service team can book you in for an  Aquarium Health Check.

Calcium in salt

Most salts are now designed to be used with RO or RODI water. This means that they have a good calcium content. If you have been making regular water changes with a good quality salt and your calcium is still too low, it could mean that your animals are using the calcium from the water to grow. In this case you will need to add some calcium buffer to slowly bring the calcium of the aquarium up to the desired level.

The Salifert Calcium Profi Test contains enough reagent to test 50 – 100 times.

Top tips:

Keep a record of you water parameter results and note what type and how much additive you use. This way you can see patterns over time to help you better maintain your aquarium.

If you need to add calcium to your saltwater aquarium, it is first worth checking that your salinity is correct. If your salt level is too low, you may see that the calcium is also low. And if the salinity is too high, you may see a high calcium reading. Get your salinity right before you change the calcium level with buffers.


There are no reviews yet.

Only logged in customers who have purchased this product may leave a review.

You may also like…

HI-772 Checker - Seawater dKH
Hanna Checker – dKH (Saltwater)
Hanna Checker - KH (Saltwater) HI-772 is designed exclusively for marine aquariums. It offers a quick, easy and highly accurate method of measuring alkalinity in dKH
not rated £69.99 Add to basket