Designed to supply reef aquaria with calcium by enriching fresh water top off supply. It uses the Kalkwasser-method and is filled with calcium hydroxide, which is intermittently agitated by a pump. It is possible to automate the system by combining an automatic level controller such as the AT-1 with the AquaMedic Kalkwasserreactor. The reactor is engineered to take a pH electrode to control the quality of the kalkwasser. An aditional advantage of this method is, that posphate is removed from the top up and the aquarium water.