Seachem Reef Advantage Magnesium

13 reviews

Seachem Reef Advantage Magnesium helps top up the important levels of magnesium on your reef aquarium, giving your corals an essential element they need to grow and develop in a healthy manner. Ammonia free, this can really make a positive difference in your aquarium.


  • Reef Advantage Magnesium 300g
    code: 636 In stock Only 5 left in stock
  • Reef Advantage Magnesium 600g
    code: 633 In stock Only 2 left in stock
  • Reef Advantage Magnesium 1.2kg
    code: 637 In stock Only 4 left in stock
  • Reef Advantage Magnesium 2.2kg
    code: 638 Available (Usually delivered in 4 days)
  • Reef Advantage Magnesium 4kg
    code: 639 Available (Usually delivered in 5 days)

Product Information

Seachem Reef Advantage Magnesium is a concentrated (80,000 ppm) optimised blend of magnesium, chloride, and sulphate salts designed to restore depleted levels of magnesium with minimal impact to the ionic ratios found in natural sea water.

If depleted these levels can affect pH and calcium levels. So, it's important to regualte the amount of magnesium. Seachem's Reef Advantage Magnesium will ensure that corals and other organisms have just the right amount for healthy balance and growth.

Unlike many other magnesium supplements, it doesn't contain ammonia. So you can be confident of both great water quality and fish health.


  • 300g treats 4,800 Litres / 1,055.9 gallons
  • 600g treats 9,600 Litres / 2,112 gallons
  • 1.2kg treats 19,200 Litres / 4,223 gallons
  • 2kg treats 32,000 Litres / 7,039 gallons
  • 4kg treats 64,000 Litres / 14,078 gallons

Directions: Use 5g (one level teaspoon) per 80 litres / 17.6 gallons, twice a week. Dissolve in at least 250ml of freshwater.

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