The Hagen company offered AquaClear Power Filter, one of the first commercially successful magnetic drive power filters for aquarium cleaning. The original version was an excellent mechanical and chemical filter. They used a foam cartridge for the mechanical filtration and a fairly large bag of activated carbon for the chemical media.
New aquarium hobbyists are sometimes overwhelmed by the choices of aquarium supplies and concentrate on the minimum to set up their new aquarium. Most retail outlets will offer kits that include the basics; tank, top, light, filter, heater, thermometer, water conditioner and maybe a choice of substrate.
This is a common tale of woe experienced by way too many aquarium hobbyists. You have decided to upgrade your filtration system, ordered the new filter from Petsolutions or your local pet store, and, as soon as it arrived, you put it together, placed it in operation and removed the old filter.
Once I started working at my first pet supplies store, I immediately started to plot how to fit more aquarium tanks into my house. At this time, most aquariums were kept in the basement (I did not have one) or the bedroom. My 30 gallon tank fit easily on top of my old desk, and the 20 gallon sat on top of my dresser.
Once upon a time we only had access to rather primitive forms of filtration for the marine aquarium. Undergravel filters were usually the filter of choice. This required the use of crushed coral or dolomite for the substrate, since sand would be too fine to work with the undergravel filter. These filters were excellent biological filters and did a fairly good job at mechanical filtration.
Don Roberts