In 1994, Ernst Pawlowsky, of Germany, introduced a new method of calcium supplementation, which soon became quite popular in the United States —  Calcium part A and Calcium part B. At the same time, Rolf Hebbinghaus, of Germany, produced the calcium reactor, and Hans-Wermer Balling, also of Germany, developed the "Balling Method" of calcium supplementation.   
  from:  
www.ecosystemaquarium.com    It will be very nice to get exact history about aquarium history.