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Seachem Laboratories Inc.

Seachem Reef Advantage Calcium

Seachem Reef Advantage Calcium

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Regular price $11.99 USD
Regular price Sale price $11.99 USD
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Introducing Reef Advantage Calcium™, the ultimate solution for maintaining optimal calcium levels in your reef tank. Crafted with precision, this concentrated, powder ionic calcium formula is designed to restore and sustain calcium levels to match those found in natural seawater.

  • Concentrated, powder ionic calcium: This powerful formula ensures efficient and effective calcium supplementation, promoting healthy coral growth and vitality.
  • Maintains magnesium and strontium: With balanced proportions of magnesium and strontium (100:5:0.1, Ca:Mg:Sr), this product supports overall coral health while preventing deficiencies.
  • Direct application: Reef Advantage Calcium™ can be easily added directly to your aquarium, simplifying the maintenance process and saving you time.
  • Non-caustic pH: Unlike traditional limewater (kalkwasser), this formula maintains a non-caustic pH (8.3–8.6), ensuring a safe environment for your marine life.
  • Preserves alkalinity: When used as directed, Reef Advantage Calcium™ does not deplete alkalinity, providing a stable environment for your reef ecosystem to thrive.

Designed for aquarium hobbyists seeking to elevate their reef tank's calcium levels, Reef Advantage Calcium™ is ideal for saltwater aquariums and marine tanks. Simply follow the recommended dosage instructions to raise calcium levels and maintain optimal conditions for coral growth. Elevate your aquarium experience with Reef Advantage Calcium™ today and witness the vibrant beauty of your reef come to life. Invest in the health and vitality of your marine habitat with Reef Advantage Calcium™ - the trusted choice for calcium supplementation in reef tanks.



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


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


After determining the calcium consumption rate, set up a continuous drip system. Use the following formula (or skip the math and use our Dosage Calculator) 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, 5 g=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.

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