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. 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. Sizes: 50 g, 250 g, 500 g, 1 kg, 4 kg, 20 kg