Seachem Reef Advantage Calcium

9 reviews

Replicate the calcium levels found in natural seawater for the benefit of your fish and corals, using Seachem Reef Advantage Calcium, aiding the development of calcium reliant coral reefs, giving them an important building material present in the water to construct their exoskeltons.


  • Reef Advantage Calcium 250g
    code: 316 In stock More than 10 in stock
  • Reef Advantage Calcium 500g
    code: 313 In stock Only 3 left in stock

Product Information

Reef Advantage Calcium is a blend of ionic calcium which will restore and maintain calcium levels to those found in natural seawater.

Corals need both calcium and carbobates to grow in both health and vitality. If these elements are depleted then corals of all kinds will fail to thrive.

As well as essential calcium, Reef Advantage Calcium also contains the optimum amounts of both magnesium and strontium.

Reef Advantage Calcium will not deplete magnesium because it does not have an acidic pH. Because of this it will not affect alkalinity levels either.

Directions for use:


  • Use 5g per 150 litres twice a week.
  • Dissolve in at least 250ml of freshwater.
  • Check calcium every two weeks and adjust amount or frequency accordingly.


  • Check calcium level
  • Follow the advice above until calcium is adjusted to 380-420 mg/l
  • Each 5 g/150 litres will raise calcium by about 12 mg/L. Quantity or frequency can be adjusted, but do not exceed 10 g/150L per day.
  • Then use as required to maintain levels.


  • After determining the calcium consumption rate, set up a continuous drip system.
  • Use the following formula to determine how much to add to your top-off water: m=vc/400 (m=grams to add to top off water, v=volume of tank in liters, c=amount to raise calcium in mg/L).

Please note:

  • Do not overdose.
  • Excess calcium may enhance the loss of carbonate alkalinity.
  • Do not directly mix with any carbonate supplement.
  • It is best if calcium and carbonate additives are added on alternate days or at least 30 minutes apart.

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