Back to Magnesium

Reef Foundation C (Magnesium) 500ml


Red Sea’s Reef Foundation C Magnesium contains high quality blended salts of magnesium. This liquid buffer is easier to dose for smaller aquariums than the powdered buffers. It is also easy to use with a dosing pump for more stability.

1 in stock


Red Sea’s Reef Foundation C Magnesium is a high quality liquid buffer.

It contains blended salts of magnesium to support healthy coral growth.

Balanced formation of coral skeleton

Reef Foundation C is designed with the reef aquarium in mind. Calcium, magnesium, strontium and carbonate are the basic foundation elements of coral skeletons. All of these elements need to be available in balanced proportions for positive coral health and growth. Therefore, these elements are absolutely essential for healthy corals and good coral growth. Maintaining magnesium in an aquarium is hugely important. Incorrect levels, as well as wild or frequent fluctuations in these important minerals, can have some seriously negative effects on your aquariums inhabitants.

In reef aquariums, corals and invertebrates rely on stable magnesium levels for their health and growth and can be very sensitive to fluctuations or general lack of these essential minerals. Magnesium is even important for fish, allowing them to grow their bone structure too.

In unbalanced conditions (eg. where there are relatively low levels of magnesium) the coral skeletons will develop with a higher proportion of calcite. This would make a coral more brittle and more susceptible to damage.

What should my magnesium level be?

As a rule of thumb your magnesium level should be roughly three times your calcium level. So if you were going to keep your calcium at 450ppm, we would say that your magnesium level should be 1350ppm. Those parameters are what we at Cornwall Aquatics would aim for in most reef aquariums. However, magnesium can be kept between 1220 – 1390ppm. The level that you choose will depend on what type of reef you have and whether you are aiming for more coral growth or more coral colouration or a happy medium between the two.

If your magnesium level is not correct it is worth measuring the salinity with a reliable salinity meter. If your salt level is too low, you may see that the magnesium is also low and if the salinity is too high, you may see a high magnesium reading.

The key to a heathy aquarium is stability

Whatever magnesium level you decide to run your system at, try to keep it consistent. Swings in the foundation levels are stressful to aquarium livestock. Regular testing is a must to ensure correct dosage and to allow you to get to know your aquariums requirements. we recommend using the Salifert magnesium test kit at least once a week. Red Sea’s Reef Foundation C Magnesium is part of the Red Sea Reef Care range. All of the Red Sea’s Reef Care Recipes use it. For best results, use in conjunction with Reef Foundation A (Calcium) and Reef Foundations B (KH) to ensure a healthy and balanced aquarium. You can learn more about the Red Sea Care program by clicking here. Reef Foundation C can also be used as a standalone magnesium buffer for marine aquariums.

Liquid supplement: 1ml will raise the Mg level of 100 litres (25 gal) by 1ppm.

Learn more about why to use Reef Foundation C Magnesium here:

Click here to see the Reef Foundation C Magnesium Material Safety Data Sheet


There are no reviews yet.

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