What about the Hamburg Mattenfilter. Best filters I have ever used, I use Poret foam for mine. The foam is the key.
The Mattenfilter, Hamburg Mattenfilter, or foam sheet filter design dates back to the 1960s in Germany. According to various reports, the filter was invented by aquarists near the city of Hamburg, hence the name “Hamburger Mattenfilter” or “HMF”. While the basic design has changed very little, the parts used today are longer lasting. Reticulated polyurethane foam invented in 1956 made the design possible. Producing reticulated polyurethane foam is a two-step process: regular polyurethane foam is produced and then the membranes of the foam are removed by combustion. This creates a maze of polyhedral cell struts without windows and a very large surface. In terms of weight/volume and specific surface area, polyurethane foams surpass most other filter media.
Filter community
T
he term filter for a Mattenfilter is actually misleading. The purpose of the foam is not to filter the water as is often assumed. The foam serves as the habitat for a vast array of microorganisms that include bacteria, archaea, worms, ciliates, flagellates, and many others. These microorganisms live in a community that is based on biofilms. The biofilms are created by bacteria that secrete extracellular polymeric substance (EPS), which is often called “slime”. The community forms a bioreactor that processes the waste and turns it into food and energy for its members, and ultimately into organic or inorganic products that are then used by plants, evaporate, or removed by water changes. It takes a considerable amount of time to establish this “filter community”; consequently, it is very important not to disturb it unless absolutely necessary. The brown filter sludge in a filter is for the most part alive and not simply waste. Removing this mud does more harm than good. The Mattenfilter with its large inflow area and specific surface is ideal to maintain the filter community long term since it works for years.
Mattenfilter working principle
The Mattenfilter works like the soil, sand, and gravel layers along creeks and river banks. This area is called the
riparian zone from the Latin term
ripa = river bank. Sediments are trapped, which creates clear water, and dissolved pollutants are processed by microorganisms, which improves water quality via biofiltration.
The Mattenfilter replaces the riparian zone in the aquarium. Since riparian zones work best when undisturbed, Mattenfilters should not be cleaned, unless the water flow get visibly reduced (i.e. the water level behind the sheet drops).
Also, it is nitrospira not Nitrobacter which converts nitrite to nitrate in aquariums. Neither is anaerobic. The Nitrobacter rquired higher level of nitrite to thrive than is found in aquariums.
Hovanec, Timothy & DeLong, E. (1996). Hovanec T, DeLong E.. Comparative analysis of nitrifying bacteria associated with freshwater and marine aquaria. Appl Environ Microbiol 62: 2888-2896. Applied and environmental microbiology. 62. 2888-96. 10.1128/AEM.62.8.2888-2896.1996.
Link to paper
Hovanec, Timothy & Taylor, Lance & Blakis, Andrew & Delong, Edward. (1998). Nitrospira-Like Bacteria Associated with Nitrite Oxidation in Freshwater Aquaria. Applied and environmental microbiology. 64. 258-64. 10.1128/AEM.64.1.258-264.1998.
https://journals.asm.org/doi/full/10.1128/aem.64.1.258-264.1998
Nitrification
B.B. Ward, in
Encyclopedia of Ecology, 2008
"Nitrification is the step in the nitrogen cycle that links the oxidation of ammonia (produced from the degradation of organic matter) to the loss of fixed nitrogen in the form of dinitrogen gas. It is performed by a few different groups of
microorganisms, including the ammonia-oxidizing bacteria, the ammonia-oxidizing
archaea, and the nitrite-oxidizing bacteria. These
microbes are all
aerobes and are predominantly autotrophic."
from
https://www.sciencedirect.com/topics/earth-and-planetary-sciences/nitrification