Red Sea Reef Foundation C – Magnesium

Red Sea Reef Foundation C is a concentrated magnesium supplement designed to maintain the magnesium levels required for healthy coral growth and stable reef aquarium chemistry.

Magnesium is one of the major elements found in seawater and plays an important role in maintaining the correct balance between calcium and alkalinity. Maintaining appropriate magnesium levels helps prevent unwanted calcium carbonate precipitation and supports the formation of coral skeletons.

Foundation C contains a balanced blend of magnesium salts and is designed to be used alongside Red Sea Reef Foundation A Calcium+ and Foundation B KH/Alkalinity.

Key Features

• Concentrated magnesium supplement for reef aquariums
• Helps maintain stable magnesium levels
• Supports healthy SPS and LPS coral growth
• Helps maintain the correct balance between calcium and alkalinity
• Suitable for mixed reef and SPS-dominant systems
• Suitable for manual or automatic dosing
• Part of Red Sea’s complete Reef Foundation program
• Available in liquid and powder formats

Liquid Dosage

1mL per 100L of aquarium water increases magnesium by approximately 1ppm. 

For example:

• 100L aquarium, increase by 10ppm – 10mL
• 200L aquarium, increase by 10ppm – 20mL
• 300L aquarium, increase by 10ppm – 30mL
• 500L aquarium, increase by 10ppm – 50mL

For established reef aquariums, magnesium should be tested regularly and the daily dose adjusted according to the actual consumption of the aquarium.

Powder Mixing Instructions

Foundation C Magnesium Powder can be mixed with RO/DI water to create a stock solution equivalent in strength to the liquid version.

Mix approximately 600g of Foundation C Powder with RO/DI water to prepare 1L of stock solution.

Alternatively, 1kg of powder will prepare approximately 1.7L of stock solution.

Once prepared at this concentration, 1mL per 100L increases magnesium by approximately 1ppm. g1.redseafish.com

Ensure the powder is completely dissolved before dosing or connecting it to an automatic dosing pump.

Recommended Magnesium Levels

The ideal magnesium level depends on the type of reef aquarium. Red Sea recommends approximately 1350ppm for mixed reef systems and around 1280ppm for SPS-dominant systems.

Using Foundation A, B & C Together

Foundation C can be used alongside Foundation A Calcium+ and Foundation B KH/Alkalinity to maintain the three major foundation elements required by corals.

Do not mix the concentrated Foundation A, B and C solutions together in the same dosing container, as this can cause precipitation. g1.redseafish.com

For the most stable results, test magnesium regularly and dose according to your aquarium’s measured consumption rather than relying on a fixed daily amount.