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Mineral Chemistry
Magnesium
A critical reef parameter - magnesium interacts with calcium and alkalinity to enable coral skeleton growth. Low magnesium causes alkalinity/calcium precipitation crashes.
Unit: ppm Code: MAGNESIUM
📖 Overview
Magnesium sits alongside calcium and alkalinity as the third pillar of reef water chemistry. It occupies binding sites on calcium carbonate crystals, slowing their spontaneous precipitation and keeping calcium and alkalinity in solution together. When magnesium drops below 1200 ppm, calcium and alkalinity precipitate out of solution as calcium carbonate dust - crashing both parameters overnight.
❓ Why It Matters
Enables stable elevated calcium and alkalinity. Component of coral skeletons. Coralline algae growth requires adequate magnesium. Chlorophyll production in aquatic plants.
🧪 Testing Methods
Salifert Magnesium Test Kit (gold standard). Red Sea Foundation Pro Test. Hanna Instruments checker.
📈 How to Raise
Magnesium chloride + magnesium sulfate (2:1 ratio) - the Balling method. Commercial magnesium supplements (Bulk Reef Supply Mag, ESV Magnesium).
🌊 Natural Habitat Ranges
Natural seawater: 1280 ppm.