Check the listing for details. SEACHEM REEF CARBONATE 250 ml Maintain Alkalinity ALK KH. Condition: New. Listed at 9.75 USD. SEACHEM REEF CARBONATE 250 ml Auction is for ( 1 ) : SEACHEM REEF CARBONATE 250 ml Reef Carbonateª is a concentrated (4,000 meq/L) optimized blend of carbonate and bicarbonate salts designed to restore and maintain alkalinity in the reef aquarium. 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. To prevent this you must provide carbonates (Reef Carbonateª) and calcium (Reef Advantage Calciumª or Reef Completeª). Used as directed, Reef Carbonateª will not deplete calcium, magnesium, or strontium which usually tend to precipitate with increasing alkalinity. Reef alkalinity should be maintained at 4-5 meq/L (11-14 dKH). Alkalinity should not be allowed to fall below 2 meq/L. DO NOT OVERDOSE: Excess alkalinity may enhance the loss of calcium, magnesium, and strontium. Do not directly mix with any calcium, magnesium, or strontium supplement. Best if calcium & carbonate additives are added on alternate days or at least 30 minutes apart. Each mL contains a minimum of 4 meq of alkalinity. Please feel free to contact me for International and combined auction shipping rates or with any questions or concerns that you may have about my products. Thank you !