The Reef Octopus 350PRO Commercial Calcium Reactor is the largest in the commercial calcium reactor line, rated up to 4,000 gallons. It's powered by the Water Blaster 12500 recirculation pump (175 watts) with silicone-carbide shafts and bearings for continuous-duty reliability. Capacity: up to 4,000 gallons Media capacity: 70 liters (18.5 gallons) Pump: Water Blaster 12500 recirculation pump, 175 watts, 2-year warranty Dimensions: 24in x 11.5in footprint, 14in body diameter, 52in height Feed requirements: requires a separate feed pump rated 600-1,000 GPH (Water Blaster 3000 suggested) Monitoring: pH probe holder in the first chamber, built-in bubble counter At 4,000 gallons rated capacity and 70 liters of media, the 350PRO is built for facility-scale calcium/alkalinity demand where manual dosing isn't practical.Compatible replacement parts: Water Blaster 12500 pump kits for the 350PRO.