It is a politically correct statement to make. In fact the entire Tunze filter method was designed in an effort to resist legislation bbeing presented in Germany in 1981 to restrict (essentially outlaw) marine aquariums. The reasons were technology insufficient to maintain animals long term and excessive pollution of the water ways from salt water being disposed of by hobbyists. Tunze and many other aquarists and aquarium companies worked to prove to the government that a safe alternative existed. I have seen 20 year old aquariums in Germany with no water changes. They were dominated by macroalgae and soft corals. I have aquariums that I have not changed water on in over a year, Nitrates are virtually 0 with the denitrators in use and the skimmer. It can be done, in fact as a general rule I only change water if things look bad for no explainable reason and then I change 25% or more or if the Nitrates or Phosphates are elivated and here this is largely because this is a cheaper and more reasonable alternative to the resins and it is better to ue resins to remove the last bits of nutrients rather than to bring elevated levels under control.
