Live Aquaria:  Quality Aquatic Life Direct To Your Door
Free Shipping!
FREE SHIPPING: See details >
Seachem Reef Advantage Calcium
Seachem Reef Advantage Calcium
Seachem Reef Advantage Calcium
Earn 10% Rewards with every shipment!

Deliver this item now, and then:
Next Shipment date:
The Auto Delivery schedule can be changed in the cart. After you order you can change the schedule in My Account or by calling us at 1-800-334-3699
Additional sizes may be available!
Additional sizes may be available!
Rewards Program


* Dry calcium supplement for coral growth in marine reef aquariums
* Helps restore and maintain calcium to levels found in natural seawater
* Raises calcium levels and also maintains magnesium and strontium

Seachem Reef Advantage Calcium is a buffered (pH 8.3-8.6) optimized blend of calcium, magnesium, strontium, sodium, potassium, and other salts designed for reef aquaria supplementation. Makes an excellent companion to Reef Builder ! Does not have a caustic pH and won't deplete magnesium or alkalinity. 1 tsp. per 20 gallons raises calcium 25 mg/L. 250 grams treats 2,000 gallons. A dry version of Reef Complete.

Beginner: Use 1 level teaspoon per 40 gallons twice a week. Dissolve in at least one cup of freshwater. Check calcium every 2 weeks and adjust dose or frequency accordingly.

Advanced: Check calcium level, then follow dosing regimen above until calcium is adjusted to 380-420 mg/L. Each dose will raise calcium by about 12 mg/L. Size or frequency of dose can be adjusted, but do not exceed 25 mg/L 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:

(t=teaspoons to add to top off water, v=volume of tank in gallons, c=amount to raise calcium in mg/L).

For example, if you want to raise calcium by 25 mg/L in a 50 gallon tank, then you would add 0.002x50x25=2.5 teaspoons into the top-off water.

Attention: 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 & carbonate additives are added on alternate days or at least 30 minutes apart.

General Information

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.

Customer Testimonials

Bookmark and Share