The Aqua Medic Reefdoser is one of those highly anticipated products that brings a smile to the face of every reef hobbyist that sees one. The integrated controller allows for precise adjustment of the on/off cycle duration for each pump over a broad time span - anywhere from seconds per minute to hours per day. The Reefdoser can automate many tasks in your aquarium system: - regular dispensing of trace elements and fertilizers into salt and freshwater systems - controlled addition of two part calcium additives in separate intervals - accurate dosing of Kalkwasser into reef tanks - regular feedings of live phytoplankton and zooplankton.