Red Sea Foundation C 5 Litres

Red Sea Foundation C is a carbonate and buffer complex that supports balanced coral skeleton formation as part of Red Sea’s Reef Care Program.

Carbonate & buffer complex for balanced formation of Coral Skeleton

Red Sea’s MAGNESIUM contains blended salts of magnesium and is part of Red Sea’s complete Reef Care Program.

Part of maintaining stable reef chemistry — see our guide to Calcium & Magnesium for how this product fits into dosing a reef tank.

Compatibility

Marine and reef aquariums only. None of the Reef Care Program supplements belong in a freshwater tank.

Reef Foundation C is Red Sea's magnesium supplement. It supplies magnesium as a blend of salts. Magnesium is the parameter that lets calcium and alkalinity coexist at reef levels — without enough of it, the other two precipitate out against each other no matter how much you dose.

Calcium, alkalinity and magnesium have to move together. Raising one on its own destabilises the other two, and a tank with high calcium and low alkalinity is worse off than one where both are simply low. Test all three before you change any of them.

It works with the rest of the Reef Care Program — the Foundation Pro test kit measures what you need, the Trace Colors supplements follow the calcium consumption, and NO3:PO4-X handles the nutrients. The liquid and the powder are the same supplement in two forms: the powder is made up into a stock solution and dosed the same way.

Dosage & Directions

Liquid: 1 ml raises magnesium in 100 litres (25 US gal) by 1 ppm.

Powder: 1 g raises magnesium in 100 litres by 1.34 ppm. 1 kg makes 1.7 litres of stock solution.

Red Sea's whole programme is built on dosing to a measured requirement rather than to a schedule. Test first, work out what the tank is actually consuming, and dose that. Red Sea publish a MyRecipe calculator that does the arithmetic from your test results and tank volume.

Dose into a high-flow area, away from the tank's inhabitants, and never dose two foundation supplements into the same spot at the same time — that is what causes precipitation. Space them, or dose them at different points in the system.

Move a parameter gradually. Big single corrections stress corals more than the low reading did.

Freshness & Storage

Every batch we dispatch carries a minimum of 6 months' remaining shelf life. Store this product in a cool, dry place away from direct sunlight, with the cap or inner foil closed tightly after each use.

Returns & Replacement

Returns are accepted within 7 days of delivery, provided the item is unused and in its original packaging. Manufacturer-sealed items cannot be returned once the seal is broken, and sale-priced items are not refundable.

If your item arrives defective or damaged, message us on WhatsApp with your order number — or email us, if you would rather — and we will replace it. Approved replacements are delivered within 3 to 5 business days. Transit damage is covered by insurance on every shipment. If tracking shows delivered but nothing reached you, tell us within 72 hours, which is the reporting window Indian couriers allow. Damage caused during installation or use is not covered; replacement spares for such cases are chargeable.

Full terms are on our Cancellation & Returns page.