Seachem Reef Advantage Magnesium is an ammonia free concentrated (80,000 ppm) optimized blend of magnesium, chloride, and sulfate salts designed to restore depleted levels of magnesium with minimal impact to the ionic ratios found in natural sea water. Reef Advantage Magnesium helps correct magnesium deficiency especially from the use of kalkwasser. Concentrated, blended, ionically balanced magnesium source Contains no ammonia Important in preventing ionic imbalance