The Vortex Dual Calcium Reactor is designed for marine and African cichlid aquariums. It raises the carbonate hardness and realises calcium ions that prevent water from accidification. The flow path design includes double tier of tubular material and vortex plates that promote CO2 dissolution. Directions: - Install the equipment accordin to the instruction. Reactor can be hang along the edge of the tank verticaly, or placed horizontaly inside the stand. - Fro tanks up to 55 gal. CO2 supplie is not necessary. Calcium will be released just by water circulation. Specifications: - Recommended water flow: 5 - 50 gph - Recommended tank size: 20 - 180 gal. - Carbonate Media Icluded - Dimensions: 17" L x 6" W x 4" H