The Reef Octopus KS250 Kalk Reactor is a high-performance calcium supplementing device designed for reef aquariums. It gently and efficiently mixes calcium hydroxide to produce kalkwasser, the fresh calcium-rich water essential for maintaining coral health in reef tanks. The reactor features a silent low-RPM motor that ensures a steady supply of undissolved particles remain at the bottom while clear, highly saturated kalkwasser is available at the top. It requires no external powerheads and includes easy-to-use thumb screws to refill with kalk powder without any messy mixing or clogging issues.