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.