2 Bottles Each with 1.2 kg2.6 lbs Seachem Reef Builder, 2.4 kg5.2 lbs Total Raises carbonate alkalinity in the reef aquarium without immediate impact on pH With long term use Reef Builder will stabilize pH Carbonates and calcium are essential to all coral growth, if either becomes deficient, coral growth will cease, followed by a rapid decline in health Used as directed, Reef Builder will not deplete calcium, magnesium, or strontium which usually tend to precipitate with increasing alkalinity Reef Builder raises carbonate alkalinity without immediately impacting on pH. With long term use there will be a tendency to stabilize at pH 8.3. Carbonates and calcium 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 Builder and calcium Reef Advantage Calcium or Reef Complete. Used as directed, Reef Builder will not deplete calcium, magnesium, or strontium which usually tend to precipitate with increasing alkalinity. Reef Builder and Reef Buffer may be used together. Use Reef Builder to raise carbonate alkalinity without affecting pH. Use Reef Buffer to raise carbonate alkalinity and pH. Reef alkalinity should be maintained at 3-5 meqL 8-14 dKH. Alkalinity should not be allowed to fall below 2 meqL. 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. Contains carbonate, bicarbonate, chloride, and sulfate salts of sodium, magnesium, calcium, strontium, and potassium. Each gram contains a minimum of 12 meq of alkalinity.