Magnetic Kalkwasser Mixing Reactor - IceCap

Kalkwasser supplementation is one of the most cost-effective methods for maintaining calcium and alkalinity in a reef aquarium, and it carries the added benefit of elevating pH and reducing CO2. The IceCap Magnetic Kalkwasser Mixing Reactor is purpose-built to take the manual labor out of the process. Rather than relying on a traditional powerhead submerged inside the vessel, the reactor uses an external magnetic drive motor to spin a stir bar inside the sealed chamber — keeping the solution agitated without introducing a component that accumulates calcium deposits and requires regular replacement.

The reactor connects to any freshwater reservoir via an ATO system or dosing pump. When the ATO delivers fresh water to the reactor, it displaces the saturated kalkwasser solution, pushing it into the aquarium. The adjustable-speed motor can be set on a timer or reef controller to run mixing cycles a few times per day, ensuring the solution remains at maximum concentration without running the motor continuously. Because kalkwasser must be added slowly due to its elevated pH, the low, intermittent flow rates typical of most ATO systems pair naturally with this reactor's gravity-drain design.

Construction is solid PVC and acrylic with a slim cylindrical profile engineered to fit under a standard aquarium stand. The reactor vessel detaches from the motor base for monthly rinsing, and the quick-fill cap on top allows powder replenishment — typically every two weeks — without removing the unit or making a mess. The sealed, airtight environment between mix cycles helps preserve solution potency and prevents CO2 contamination that can degrade kalkwasser quality.

Three sizes are offered: Small (~1 gal, suited for tanks up to 100 gallons), Medium (~2 gal, up to 200 gallons), and Large (~3 gal, up to 300+ gallons). All three share the same 25" height and the same core feature set. An ATO system, dosing pump or timer, and calcium hydroxide powder are required for operation and are sold separately. The motor is not rated for continuous use and should be run on a periodic schedule.