Seachem Reef Advantage Calcium 1kg


Seachem Reef Advantage Calcium 1kg


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Seachem Reef Advantage Calcium 1kg

Reef Advantage Calcium™ is a non-caustic (pH 8.3–8.6) optimized blend of ionic calcium designed to restore and maintain calcium to levels found in natural seawater. Calcium and carbonates are essential to all coral growth. If either becomes deficient, coral growth will cease, followed by a rapid decline in coral health.

Reef Advantage Calcium™ also includes magnesium and strontium in amounts proportionate to typical utilization ratios (100:5:0.1, Ca:Mg:Sr). This allows one to maintain these two important elements while maintaining calcium. Unlike limewater (kalkwasser), Reef Advantage Calcium™ does not have a caustic pH and will not deplete magnesium. Used as directed, it will not deplete alkalinity.


BEGINNER: Use 5g (1 level teaspoon) per 150L (40 US gallons) twice a week. For precise dosing, use the Seachem Digital Spoon Scale. Dissolve in at least 250ml (1 cup) of freshwater. Check calcium every 2 weeks and adjust amount or frequency accordingly.

ADVANCED: Check calcium level, then follow addition regimen above until calcium is adjusted to 380–420mg/L. Each 5g/150L will raise calcium by about 12mg/L. Quantity or frequency can be adjusted, but do not exceed 10g/150L per day. Thereafter, use as required to maintain calcium.

EXPERT: 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). [For reference: 1 gallon=3.8 liters, 5g=1 teaspoon].

DO NOT OVERDOSE: Excess calcium may enhance the loss of carbonate alkalinity. Do not directly mix with any carbonate supplement. Best if calcium & carbonate additives are added on alternate days or at least 30 minutes apart.


Calcium Chloride, Magnesium Chloride, Strontium Chloride


Amounts per 1g 

  • Calcium (Ca) (min) 335mg

  • Calcium (Ca) (max) 347mg

  • Magnesium (Mg) (min) 17mg

  • Strontium (Sr) (min) 0.34mg

CAUTION: Causes serious eye irritation. Keep out of reach of children. Avoid contact with skin.


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