Seachem Reef BuilderSeachem Reef Builder supplies the carbonates and calcium which are essential for all coral growth. It also raises carbonate alkalinity without immediately impacting water pH, and will stabilize aquarium water at pH 8. 3 with long term use. Raises carbonate alkalinity (KH) with minimal pH impact Provides a blend of carbonate sources that will not lower pH Will not deplete calcium, magnesium, or strontium Promotes healthy coral growth If either calcium