Reef Builder™raises and maintains carbonate alkalinity (KH) without directly impacting pH. It replenishes calcium, magnesium, and some trace elements often precipitated when alkalinity is raised. Marine Buffer™raises both pH and carbonate alkalinity, while Reef Builder™raises only alkalinity and replenishes calcium, magnesium, and strontium. To control pH and alkalinity, use Marine Buffer™.To promote growth of corals and avoid unstable KH and fluctuating calcium concentrations use Reef Builder™,alone or with Marine Buffer™.A 250 gram bottle treats 800–1600 gallons.