Seachem reef fusion 1 and reef fusion 2 are the foundation of a system formulated to provide the essentials for the reef aquarium reef fusion 1 provides calcium while reef fusion 2 provides alkalinity when used together the reef fusion system will maintain calcium and alkalinity levelsreef fusion 2 contains a mixture of carbonates and bicarbonates at an alkalinity of 4400 meql it is designed to restore and maintain alkalinity in the reef aquarium and provide calcareous species with the es