Precision Marine KR-620 Professional Kalkwasser Reactor (PM). **** PRODUCT MANUAL **** There are two ways Calcium can be added to your reef tank, the Calcium Reactor or the Kalkreactor pictured here. You can either gravity feed through the Kalkreactor from a freshwater top-off system to your reservoir, or use a dosing pump. We chose a reliable water pump in lieu of the magnetic stir bar, which tends to jam, bind and wear the acrylic. Our model also includes a threaded opening at the top to enable adding Kalk powder without removing the lid. Master fabricated and computer cut, the KR620 is a very nice piece of equipment. KR-620 Specifications: - Overall Height: 20" - Reaction Tube Diameter: 6" - Reaction Tube Height: 18" - Base Diameter: 7.75” - Water inlet and outlet size: 1/4" Polypropylene tubing - Method of feeding: Gravity or Pressure - Supplied Water Pump: Maxi-Jet 400