The following is an excerpt from a now out-of-print book published in 1998 titled Aquarium Ecology. The book covers a very wide range of topics. Its value today is derived, at least in part, from its many technical explanations. These explanations often expose some of the research that was behind the development of the tools and techniques we aquarists might now take for granted. It’s reprinted here today in hopes that some will find value in learning a bit more about the development of our hobby and that it might also inspire the current generation of aquarists to continue the rapid development of our hobby.
This selection has been edited for clarity.
Investigation into the necessity of water changes and the development of the Comline system.
by F. J. Wichowsky
After having completed my studies of biology in November 1983, I was an executive employee within the Aquarium & Terrarium Department of the Zoological Gardens of Munich (Hellabrunn) in the Federal Republic of Germany for about one year. From 1985 to 1987 I was the scientific manager of the test laboratory of Tunze Aquarientechnik GmbH in Penzberg, Germany. Within the framework of this occupation, which was supported by the Federal Ministry of Research and Science, I was in charge of several experimental aquariums inhabited by tropical fish and plants.
Among other things, Tunze Aquarientechnik GmbH has made it its business to give aquarium technology a new impetus by employing modern scientific methods. One central feature in this endeavor is the operation of an aquarium inhabited by living organisms under conditions as close as possible to those found in nature. The auxiliaries used in the system are pumps, skimmers, bioreactors, and Osmolators of the Tunze System, and biological know-how. Natural conditions are achieved if biological and chemical cycles of bodies of water, i.e. the decomposition of harmful substances, can be imitated in the aquarium. The most important process is to convert the harmful substances, which are released into the water by one kind (fish, for example) into substances which can be used by another kind (plants, for example) or to remove them and thus render them harmless by a technical device such as a filter or bioreactor.
Up to now, the operation of an aquarium required the so-called “water change” at regular intervals due to accumulation of nitrogenous compounds and the resulting pollution of the water. Because of this many thousands of liters of salt-containing waste water has been and is produced per year. This habit of water changing does not only produce a certain environmental pollution, but also entails an incalculable danger for the inhabitants of the aquarium. This is reason enough to make this process superfluous as far as possible! In a three-year scientifically based investigation we have been able to substantiate that this is possible. For about two and a half years measurements of the most important water parameters have been carried out every day, which in a very detailed form prove that under the right conditions water changes can be dispensed of within a successful coral reef aquarium.
In modern aquarium technology, filtration is of great importance for several reasons. For one thing, the beauty of an aquarium demands crystal clear water. But, in order to keep the fish healthy, it is much more important to limit the invisible substances, which have been dissolved, respectively to convert them into compounds that may be used by plants in a biological cycle.
For this reason, effective filtration will always consist of at least two stages. First, a mechanical filter which should be designed as a high-capacity, quick-change filter, this lead to the development of the Tunze’s Comline system. And Second, biological degradation “filter” in the form of a biological reactor [or bacteria laden substrates].
This mechanical quick-change filter is used to eliminate all visible turbidity from the water in a very short period of time. This water turbidity consists of particulate waste caused by dead plants, uneaten food, fish waste, etc. As this waste dissolves and causes the quality of the water to deteriorate, a good mechanical filter has to be capable of meeting two requirements: a high capacity and the ability to be changed quickly and easily.
Since the 1980s Tunze Aquarientechnik GmbH has been using filter cartridges made of acrylic wadding wound in layers and set by a special process. In biotechnology, this type of filtration is known as deep-bed filtration, separation takes place by adsorption, i.e. the particles settle on or stick to the acrylic fibers or are held there by their electrostatic action. Colloids can also play an important part as retaining elements (“adhesives”). The better the aquarium has been tuned biologically, the more efficiently the filter cartridge will operate. Depending on the level of contamination, the filter cartridge has to be replaced or washed out twice or three times every three weeks, and the Comline system allos this to be done quickly and easily.
In the event of chemical contamination after use of medication or extensive yellowing of the water, Comline cartridges can be filled with activated carbon. This equipment can best be thought of as being like a ready-to-use fire extinguisher. The ease with which Comline cartridges can be changed, their low cost, and their great versatility are what make them an excellent tool for successful reef aquarist everywhere.
These days there is no shortage of media reactors available. The Tunze Comline series is still chosen by many for its low cost and extreme ease of use.