Product overview
Red Sea Foundation C Magnesium+ is a liquid magnesium supplement for marine tanks. Skimming and coral calcification pull foundation elements from the water. If magnesium is too low, calcium and alkalinity are more likely to precipitate, which can stall growth and dull colour.
It is a concentrated mix of magnesium salts balanced to the chloride/sulphate ratio of natural seawater, for use with Red Sea’s Foundation calcium and alkalinity additives.
Key features
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Ionic balance: Magnesium salts to hold the ratio that helps keep calcium in solution.
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Calcification: Stable magnesium supports normal coral skeleton formation.
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Buffering: Helps pH, alkalinity, and calcium stay in a workable range in high-demand reefs.
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Liquid ions: Ready to use without converting dry salts in the tank.
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Low residue: Inorganic salt mix; not an organic food, so it does not add the same waste load as coral foods.
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Precipitation: Formulated to limit crusting on dosing tips and pumps.
Water and system compatibility
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Water: Marine and reef aquariums only. Not for freshwater or planted tanks.
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Livestock: SPS, LPS, soft corals, and calcareous algae.
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Doser: Stable unrefrigerated and unstirred in a dosing container.
Dosing and instructions
Always follow dosage & directions on product packaging.
Calculate true water volume. Typical daily use per 100 litres, aiming for 1280–1380 ppm magnesium:
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LPS / SPS frags and growing tanks: 1 ml (raises Mg by about 1 ppm)
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Mixed reef: 1 ml (raises Mg by about 1 ppm)
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SPS-dominant: 2–5 ml, matched to skeletal uptake
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Ultra-low nutrient (ULNS): Dose to match measured uptake of Foundation A (calcium) and B (alkalinity)
Magnesium moves slowly but should stay stable. Test before large changes. A Red Sea Magnesium Pro test kit is suitable. Do not raise doses without testing.
Storage
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Bottle: Cool, dry cupboard out of direct sunlight. Do not refrigerate or freeze.
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Doser: Flush lines with RO/DI water from time to time so delivery stays accurate.
Specifications
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Brand: Red Sea
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Range: Reef Care Program (Reef Foundation)
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Size: 500 ml / 1000 ml
